This book's target audience is the novice C programmer who needs to implement data compression of some kind. The authors go to great pains to explain exactly how the code works, but they don't do as good a job on the algorithms themselves. If you are a competent C programmer and/or have any formal training in algorithms, this is probably not the book for you, though it may be a good jumping-off point if it's the only book you can get your hands on.