David Heinemeier Hansson's review of Refactoring: Improving the Design of Existing Code 1st Edition

Refactoring: The fundamental before/after book. Here’s some code that could be better, here’s how to make it better. The trick to reading this book is to carefully read through every single refactoring pattern and then try to apply it on your code base (you don’t have to commit if it doesn’t fix things). You can’t just blow through it or you won’t really learn it. And you can’t just say “oh, I’ll look up a refactoring when I need it” — because then you don’t know what to look for.

Ref:: https://signalvnoise.com/posts/3375-the-five-programming-books-that-meant-most-to-me