Just started to read the book Working Effectively with Legacy Code by Michael Feathers. The book is about how to make changes to legacy code while minimizing the risk of introducing bugs, as well as other issues when dealing with legacy code (maintainability).

So far (only read the first 50 pages or so), the book does a good job explaining why you need tests. This is not something new but the book explains it rather well and it feels like the bo ok is more geared towards a practical approach than for example Refactoring by Martin Fowler. Some of the bullet points so far has been breaking dependencies in the code, making it possible to write unit tests. I couldn't agree more, breaking dependencies and making it possible to inject a mock object into your class is extremely valuable. It makes it so much easier to write the tests when you have your class in complete isolation and you can dictate the environment which the class is executed in.

I've got high expectations on this book and so far Michael Feathers has delivered. Highly recommended.
I do intend to continue publishing little book reviews while reading and when I'm finished with the book I'll compile a complete book review.