I read the book shortly after it came out, when I was working on an enormous system of legacy code. Unfortunately, I didn't find the book particularly helpful in terms of strategies for understanding or modifying legacy code. Yes, tests are a good thing, but I expected the book to provide a lot more.

I agree with the parent comment that it is useful to follow the "trail" through the code. It can be a big effort just to figure out how the pieces are connected. Figuring out the data structures and files is another important thing. Also, write documentation as you go; this will help others understand the big picture. If you can just jump in and start writing meaningful unit tests, your legacy system is kinda trivial :-)

Overall, there are people who view testing as a useful tool and people who view testing as an ideology. This book falls into the latter category.

>> Yes, tests are a good thing, but I expected the book to provide a lot more

It is strange, actually, how much value we place on any information that sits between two pieces of cardboard.