Here are a few comments from past participants in Allen's classes and beneficiaries of his consulting work:

That was the best instruction on software development I've ever had.

...as a noob it's tough to figure out who to believe just in reading. Having you take us through your instruction made you our reference source.

-Barry Schwartz, NetApp

Allen is a software development renaissance man, truly expert at a mind-boggling array of subjects. In the months that he contracted with our company, he employed several methods to seriously improve our capability. He worked with teams on complicated OO models, presented seminars (design patterns, agile development, requirements engineering), mentored key staff, reviewed models and code, and even produced a lot of code himself. And he did everything with a practical focus. He was also fearless in speaking truth to power and identifying the root causes of issues, whether they were technical, political, or just irredeemable employees. The real tribute to his contribution is that since his engagement, we talk about things differently. The conversation has changed--for the better.

- Alan Freedman, pearl.com

...when we determined to move all of Schwab's application development to a single platform, we realized we needed to engage a few thought leaders to help. Allen was one of those. He'd been teaching programming and programming best practices through UCB Extension -recommendation enough. But we found more: a partner willing to map out a learning strategy for our developers; and an educator who truly excelled at rapidly engaging our staff and moving us in our new direction. Later, when I started SVForum's Software Architecture and Modeling SIG, Allen was kind enough to share his insights and experience in design patterns, frameworks, MVC, non-MVC, AJAX and more in three talks over five years. Allen is superb at riding the leading edge of technical trends, embracing understanding and imparting technique and wisdom.

-Ron Lichty

Allen is consummate software professional. I engaged Allen on a contract to build a complex, high throughput transaction processing service. He very effectively worked with the rest of our team, mentored the team members and single-handedly implemented a rock-solid subsystem for us. His tremendous experience in architecting highly reliable software, his TDD approach, wise and careful selection of tools and frameworks for the job and just very careful and extremely well documented code contribute to the quality of the final outcome. Allen possesses a rare combination of advanced theoretical knowledge and hands-on, crank it out experience.

-Thomas Kudrycki, CTO eCurrencyMint

I have had the pleasure of working with Allen and learning from him for more than a year at JustAnswer and PEARL.COM. During that time Engineering team was moving to an Agile process and a lot of process related questions arose daily. Allen showed himself as a true professional consistently suggesting "think outside the box" strategies that really worked. On top of that he is just a very pleasant individual to interact with. I also took his Agile workshop. Four days and total of more than 30 hours. If somebody can make it interesting, keep the group excited and share tons of useful techniques, practices and strategies that can be applied right away, that would be Allen Holub.

-Andrey Boreyko, pearl.com

Allen is one of the best software architects that I have met. I have attended a number of courses offered by Allen from the early days of C++ programming to design patterns to OO-Design and Programming. I also engaged Allen in teaching OOD design and programming to engineering teams in two relatively large capital equipment companies. It was well worth the investment in time and money. His in-depth knowledge and approaches to OO-Design process were insightful and encouraging to most software developers and the community. I highly recommend Allen.

- James Yu

Allen is a leader in the field of object-oriented architecture and design. His opinions are rooted in a rare understanding of how technical realities map into mental models, and this leads to solutions that are vastly higher quality than the cookie-cutter solutions one sees from too many consultants. I last worked with Allen on a project that combined new algorithms, new technologies, and new hardware. That is the type of challenge for which most consultants would produce an infinite sequence of "On the one hand...on the other hand..." discussions, but not Allen. He came up-to-speed very rapidly and was soon shuttling back and forth between whiteboard and keyboard, advocating for particular architectural and design decisions. One thing that I've come to appreciate more in recent years is Allen's integrity. One would like to think that honesty, work-ethic, and opinions rooted in real experience and not trend-chasing were the rule and not the exception, but I now know how rare such qualities are. I am confident that Allen would provide excellent value for any company wise enough to engage his services.

-Larry O'Brien

Allen Holub is one of the best educators, consultants and thought leaders that I have had the pleasure to work with. He has a great ability to distill extremely complex and technical topics to understandable, digestable chunks. I'd be very excited to work and interact with Allen again.

-Alex Wong

I have respected Allen's work for years. He's been around the block more than a few times and clearly brings that practical experience to his writings and his talks.

-Scott W. Ambler

I've followed Allen's work in software design for many years. I felt privileged to get to know him personally at Software Architect and interact with him as a co-equal. His depth of insight and practical craftsmanship is unparalleled. I felt humbled in the presence of such intellect, yet gratified by Allen's openness and keenness to engage in all areas of mutual interest, from business to technical to hobby and the world in general. If you ever have the chance to engage Allen, I couldn't be more enthusiastic about recommending that you use that opportunity.

-Howard Deiner, Owner, Deinersoft, Inc.

Allen came to our organization as a software design consultant/architect and agile coach. He has an outstanding grasp of OO design and design patterns. He communicates clearly and effectively. I learned a tremendous amount from him and I am a much better developer than I was before he visited. Allen was a pleasure to work with; he has a calm, inviting demeanor making it easy to work with him. I especially appreciated his common sense and honest approach to problems, both technically and organizationally. I was very sorry that Allen had to leave and I would gladly work with him again in an instant. I give Allen my highest recommendation.

- Pete Gowdy, Sr. Software Engineer, Pearl.com

I had the pleasure of working with Allen at Pearl.com, where he helped lead our team in adapting and learning agile methodologies while building products for our Professional community. He is a great communicator and teacher, and cared deeply about the users for whom we were designing. He is very knowledge about software design and processes, and is a strong colleague."

-George Gerard, Associate Product Manager, Pearl.com

Allen and I have spoken at conferences (most notably SDWest), and I have always considered it a privilege to be considered in the same class as he--his insights into technology have always fallen into the category of "leading-edge", and things he's said end up becoming "widespread knowledge" within five years. Were I a company looking for somebody to help me navigate down the path of new technology, I can't imagine a better person to have as a guide than Allen.

-Ted Neward, Principal, Neward & Associates

Allen and I regularly give advice on the various Agile forums [on LinkedIn]. Allen is one of a select few among those who give advice who I would consider a true peer, an equal. Sometimes we disagree, and I think we both find those occasions provide an opportunity to learn. In such matters, his advice is about as good as you will get.

-Paul Oldfield, Process Engineer, Capgemini

I've worked with Allen off and on over the course of many years. I know him to stand out from the crowd as a thorough professional with a deep knowledge of a range of programming languages and software design generally. He not only knows it, he communicates it effectively. Allen can explicate complicated ideas with remarkable clarity and without dumbing it down. He is understandably in demand as a writer, lecturer, and consultant, because he is good at all three.

-Michael Swaine, Editor-in-chief/Associate Publisher, Dr. Dobb's Journal

I had the pleasure attending Allen's UCB courses on Java and OO design, and more recently a custom, corporate training program that Allen delivered on how to enhance our adoption of Agile methodology. A smart customer can derive incredible value by tapping Allen's broad spectrum of expertise and deep insight into the organizational culture and technical architecture."

-David Golden, was Allen's client

I learn something deep every time I talk to Allen or watch him present. Hire him to consult for you and let him work with your experienced grey-beards or your energetic new hires. Your company, your most important projects, and your people will be better for it."

-Daniel Steinberg, Author, Podcaster, Trainer, Coder, Dim Sum Thinking

I saw Allen's packed presentations at Java One on Concurrency (among the best there) and contacted him about doing an audit of our codebase, which had a lot of threading. He tore through the source, made a list of issues, and we constructed an agenda. He presented to the developers, explained a lot of things, fielded questions. Great. Since then, I have had many occasions to discuss software with Allen (and to see him present at conferences) and have always found him to be one of the best people out there. He's a rare blend of highly abstract and deftly comfortable with details, however piddling. One minute you can be talking about the reason for design patterns like Bridge, and the next, comparing notes on how difficult or easy it is to configure Hibernate. His patterns book is great, btw."

-Rob Williams

Over the years, Allen has consistently given our company's software development team excellent advice about ways to go about our work. In each case that he served as an Expert Advisor to us, his advice stood out for its clarity and turned out to put us on exactly the right development path. This was true both when Allen advised us about specific structures within our software and when Allen helped us choose broad strategies of how to move forward. All that and a really pleasant guy!

-Andy Robin, CEO, Ascenium Corp.

Allen has been a key technology advisor to Ascenium throughout our existence. When we began to design our compiler, many industry experts were of the opinion it couldn't be done. Allen's wisdom, creativity, and experience guided us towards a solid and successful architecture that we now reap the benefits of every day.

- Robert Mykland, CTO, Ascenium Corp.

Allen Holub has taught a generation (or more) of programmers how to program in C, C++, and how to best apply object oriented techniques. His projects in Dr. Dobb's Journal and other written venues are legendary and models of great coding by any measure you care to apply. What sets Allen apart from many other people that have similar technical backgrounds? Two things, at least. First, Allen isn't just a coder and designer. He's a writer. That ability to communicate his ideas makes his ideas more valuable. Second, while he became very well known for C programming, he didn't rest on his laurels and has stayed current with the latest technology. He's worked in and written about C, C++, Java, Patterns, AJAX, Web Services, and probably a half a dozen other things I've forgotten about. It is always an honor to write for magazines like Dr. Dobb's Journal. it is even more of an honor to write for them for 30 years! There's a reason publishers like Dr. Dobb's want to publish Allen's work. It's topical, its insightful, and readers enjoy learning from it. I might add, I was one of that generation that benefited from Allen's sharing of his knowledge. Thanks Allen!

- Al Williams, Contributing Editor, Dr. Dobb's Journal,

I was a student of Allen Holub's on more than one occasion as I sought to increase my skills and understanding of Object Oriented Programming in Java. I found both Allen's books and classroom approach to be effective and useful resources. He explained topics clearly, showed patience when there were challenges to understanding, and he demonstrated a deep and comprehensive command of the subject.

- Robert Dunlop, Advanced Systems Engineer, Electronic Data Systems,

Allen is a most excellent combination of smart and articulate. He understands, deeply understands, a wide variety of technologies. Just read his books to understand how deeply he gets technology. But more importantly, Allen can communicate his deep understanding of technology both in writing and verbally. Just read his books. Or hire him to train (kinda like a try-before-you-buy). Or just bring him in to give constructive suggestions about how you can improve your systems. But once you get to know Allen, you will understand just how good he is and you'll want more of his time and more of his knowledge.

- David Pollak, Founder & Distinguished Committer, Lift

There is a LOT of buzz these days about "Agile" and "Devops" guru's and technologies. There appears to be a bit of high-powered blend between old-school and new-school in the technology universe! Allan has and can scan the entire spectrum of the current software and architecture comos. I have been graced with the great fortune to have taken classwork and direction from Allan relating to the java and agile software development for over a decade. Allan is truly a "Seal Team Six" instructor, when it comes to getting your "troups" up-to-speed and effectively deployed to build great products! In summary, Allan is a world-class expert that can greatly enhance your companies bottom line!"

-Todd Thal

I had the good fortune of taking one of your C++ classes at Berkeley Extension in the mid-80's. That class provided me a solid footstep onto the path of my nearly 30-year career in software.

John Fleishhauer (in 2013)

[The OO Workshop] was a humbling experience even for our most senior OO programmer. I believe I [now] understand OO's fundamental principals and how they're applied. I believe our team now understands that as well. However, I do anticipate bringing Allen back in at various points in our analysis and design phase to offer his critique and help us in our application. Do we do everything right? No! But we do it far better now than we did before.

Looking at our code now, I feel much better about how it's organized, about how it performs, and about how easy it is to maintain.

... would I do it again? Absolutely!

-Bill Hamilton, MTS Techchnologies.

(Bill's complete 6-page letter, which has some good advice about the OO-adoption process as well as a review of Allen's class, is at /company/recommendation.html.

The ability to design a system architecture is the most important and most powerful tool that a developer can possess. But it is a skill that is difficult to learn, and one that is almost impossible to teach. Allen Holub's design training workshop does a great job of doing just that...

In short, [the Agile/OO Workshop] is a tremendous learning experience for any object oriented developer who is serious about their craft.

-Eric Armstrong

(Eric's complete comments are on his blog: http://www.artima.com/weblogs/viewpost.jsp?thread=24085).

I was highly impressed by [Allen]...

Allen's depth of knowledge is awesome. I have never heard a presenter talk about the Java language with such understanding and background, with the exception of some of the Java architects from Sun (e.g. Joshua Bloch and Neal Gafter).

Allen had extensive course materials--from his web site I printed out more than two inches of documentation. He started the course talking about object oriented design and included analysis of a case study (the "Bank of Allen"). We then did our own object oriented design case study as homework. We also covered basic UML and topics such as interfacing with managers and other people involved with projects. As we got into language specifics we started with a brief overview of Java essentials so as to highlight some of the "corner cases" in the language. We emphasized such topics as threading where coding is more complicated, then concluded with AWT and Swing.

My personal experience prior to taking Allen's class was as a Java programmer for about two years with a total industry experience of ten years. I also have a bachelor's in math-education and a master's in math.

-Kai Middleton

Thanks for your dynamic and professional talk about Tiger 1.5 to the EBIG Java SIG. I am hearing great feedback and it looks as though you got some great discussion started. Your expertise shines through and you have a great sense for speaking for telling “reality” – how it is, the good the bad and the ugly. Users really appreciate you sharing your knowledge with them. We appreciate you taking time to come to our Java SIG and talk with ebig folks.

- Kristen Kuhns, Executive Director, www.ebig.org

The discussions/design work with the other students was great. The "practice" really helped to illuminate the concepts.

- Clay Bennet

Of the OO Workshop: It was just what I needed. Thanks!

- Scott Gould

Of the OO Workshop: Best course I took on OO (out of three).

- Tarak Fekih, Logitech

One of the reasons that I selected this class was that I felt it would give me an accurate introduction as to what OO design really is. I got that and more. Anybody can create an object---I needed to learn OO design. Good class.

- Chris Breazeal: Sr. Product Developer, BMC

If I had found this knowledge earlier in my career, life would have been a lot more pleasant.

- Todd Thal: Web developer, doubletwist.com

This was a very instructive course. The portions covering design and process were inspiring. I have read many of Allen's writings and now have completed his course, and I believe he has much to offer the software community. I am excited about software again!

-Bradly Smith

His course offers some very useful information about the OO-Design process, and challenges most programmers to think about software design in ways that can be difficult (and enlightening) compared to their current design practices.

Allen understands this material very well, and present it in a way that keeps the student's interest high.

-John Beltran, Autodesk

Allen always has well informed responses to questions. I have learned and understood more this week than I have in quite a while.

-Rebecca Jones, Innovative Interfaces, inc.

A very thorough coverage of OO Design, with great attention to detail.

-Eddie Dickie, Innovative Interfaces, inc.

Allen is an excellent, engaging, and immensely knowledgable instructor. The material covered is really not covered elsewhere.

- Craig Kapfer, Lawrence Livermore National Laboratory

Allen is a very attentive and patient instructor, and goes out of his way to make sure each concept is understood by everyone. No one should feel left behind. An extremely useful and instructive course.

- Jo Stockley

I'm a physicist at Lawrence Livermore Lab who took a ten-week C++ course taught by Allen Holub at UC Berkeley in spring, 1997. At that point I'd done a great deal of Fortran programming and a fair amount of C, but had had no exposure to object-oriented methods or to C++. Although the pace of the course was rapid, I managed to keep up, and learned the methods that are now the mainstay of my C++ scientific programming. Mr. Holub was a clear and enthusiastic instructor, and devised a set of homework assignments which nicely demonstrated general object-oriented techniques while also introducing specific C++ syntax. Mr. Holub's course was well worth the investment of time and money.

-Robert Horton

I would strongly recommend this course to any OOP engineer needing to get a genuine grip on the design process. The sequence of hands-on exercises provide a very real and understandable glimpse into a design methodology that could reduce total project time and wasteful debugging

- David Vinson, Best.com