Vigen Isayan emailed me today to ask:

What book(s) you would recommend for learning 1. design patterns, and 2. concurrency programming.

Off the top of my head:

1. For Design Patterns, the greatest is still the original “Gang of Four” Design Patterns book. The design patterns are mostly universal, and the implementations happen to focus on OO techniques (dynamic run-time virtual dispatch etc.) but you can also express many of the patterns using generic programming (static compile-time templates etc.) – for example Observer becomes really simple. The book is almost two decades old, has inspired huge numbers of follow-on patterns books, and there’s still none better of its kind that I know of.

2. For concurrency (and parallelism), check out my 33 articles on Effective Concurrency. I hope to assemble them into a book in the near future. In the meantime they’re all out there online freely available.

If you have additional recommendations, please post them in the comments. Thanks.

On a personal note

Speaking of the Gang of Four, here’s a personal story I don’t know if I’ve shared on the blog before:

At the time it first came out, I was working in downtown Toronto. We had a really excellent local bookstore that specialized in programming books and magazines (alas, it’s long gone now). On lunch breaks, I would go there to browse and get new books to absorb. Note that this was before I was a published author myself, and I had no idea about major new books coming out, so I had no warning of what was about to happen.

On one day that at first seemed like any other, at lunchtime I was browsing the shelves as usual, and I saw copies of a white and blue hardcover book I’d never seen before. Curious, I picked up a copy. It had an unusual title, Design Patterns. I had never heard of the book or its authors before, knew nothing about it at all, and so was quite unsuspecting when I opened it and something happened that I had never experienced before and haven’t experienced since (so far):

I opened that book for the first time, stood there paging through it for less than five minutes, and knew immediately and profoundly that I was holding a classic in my hands. The realization was so unexpected and surprising, it hit me almost physically. At first sight, it was as easy to recognize this book as an important leap forward as the first you see an airplane flying in the sky. Scales fell from my eyes: Cataloguing OO design problems and their known solutions! Imagine!

I had already learned a few of the patterns on my own here and there, some through hard work and experience, others by combining ideas from various articles, many by working with experienced colleagues. But suddenly I found myself standing there in the bookstore aisle just absorbing one problem and solution after another after another, and feeling my understanding begin expanding. Even the patterns I sort of knew about were explained with concise clarity: Motivation, the problem and the specific constraints on the solution which are so important because they affect the design. Known solutions. Variations with tradeoffs.

Bliss! No, more than bliss — treasure.

This must be what explorers and hunters feel like when one day unexpectedly they discover an unopened and unransacked tomb of a young Egyptian Pharaoh, a sunken treasure galleon filled with precious cargo and artifacts, or a cave near the West Bank containing well-preserved two-thousand-year-old scrolls of important literature.

And Design Patterns was language-agnostic, to boot.

Nineteen years later, it’s still at the top of my list of design books to recommend.

Disclaimer: Something this profound inspires a whole new subculture. Later “pattern” wannabe books often went way, way, way overboard, some of them almost to the border of quasi-mysticism. Ignore most (not all, but most) of the follow-on pattern books. Only a few are worth your time; read the reviews carefully first.