I use make for a variety of tasks. In addition to managing code compilation, I also use it to manage LaTeX document preparation. Before getting this book, I had cobbled together some (pretty clunky) makefiles that got the job done, but I wanted to do a better job and understand some of the snippets of makefiles that other's had shared with me; that's why I got this book.
The book is good, and contains a wealth of detail. However, it dives right in and makes a lot of assumptions about the reader's programming experience. For example, in the first motivational example, the author presents a program that counts the number of times different words appear in the input via the command line. No big deal, right? Well, he uses lex in that code. I get what he is trying to do; he's trying to show that make can do more than just call a compiler like gcc, but if you don't know what lex is, you're going to get all hung up on that. As you read the book, you need to keep a lot of place-holders in your head to keep track of things that have been introduced but not explained; as often the explanation comes much later on. I'd suggest that laying down a firmer foundation and holding the reader's hand early in the text would make the book a whole lot more accessible.
I did find this book useful, and I'm glad that I have it. I gave it three stars, though, due to the issues I've outlined above.