Book review: Working effectively with legacy code

I finally finished “Working effectively with legacy code”, reading it a few pages at a time every morning on my way to work. Legacy code is one of these topics you know are important, but which you never really want to hear about, so the book has stayed on the backlog for a while. Recently, I helped out someone establish tests on a legacy code base, and began following Michael Feather’s tweets with great enjoyment, and decided it was time to read it.

Who should read it?

The developer who is already familiar with unit testing, comfortable with his language, object-oriented concepts, and what makes code maintainable - and wants to expand his thoughts and tools on testing and testability.

3 things I liked about it

3 things I didn’t like that much

Parting thoughts

I really enjoyed this book, but I would recommend it with an asterisk. Depending on how you want to look at it, a polyglot book will either lose specificity, or gain generality. Personally, I think in this case, the gain in generality easily compensates for the lack of depth in each individual language. Yes, I would like a C#-specific book which points to useful, up-to-date tools – but that book would be obsolete in 2 years at best. By covering a variety of languages, Feathers illustrates very different solutions or ideas, and because he uses only fairly simple features in each language, the ideas remain easy to understand and convert into other “coding dialects”.

My personal bent is for concepts and language, because they last longer than recipes and tools, which is why I really enjoyed this book: it helped me create / articulate a mental map. I don’t have many computer books published in 2004 that I read for insight, today – and this one feels like one of these “timeless classics”.

That being said, I think it takes a certain experience with unit testing and code maintenance to appreciate the book, and I wouldn’t recommend it to someone who is just starting with tests and wants to find quick solutions to their problems. It may work (the book is very clear on steps and methodology), but I suspect it may be potentially frustrating.

Totally unrelated note: this is the first technical book I read on Kindle, and I have mixed feelings about it. I was hoping that the Kindle could serve as a portable library for all these massive technical bricks. On one hand, it’s nice to have the possibility to carry around searchable books; on the other hand, clearly, it’s not the best way to read through code samples, where good old paper still has an edge.


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