Classifies swimmers into 6 types (e.g. The Arnie (competitive, naturally athletic; kicks from the knee rather than the hip, creating drag and lowering the legs in the water), The Kicktastic (has a dominant kick to make up for a poor arm stroke, which is reflective of where they left off learning to swim as a child; has a good body position the water)) -- and suggests specific drills to help each type overcome its particular stroke, breathing, and mindset flaws.
Recognizes that swimmers have different physical attributes, personalities, and swimming experience and goals, and thus doesn't aspire to teach a single, "ideal" stroke. Suggests that for some swimmers or under some circumstances (e.g. the open-water portion of a triathlon), a choppier, quicker stroke may be preferable to the long, smooth stroke that you see in the Olympics.
I haven't tried to apply the advice in this book, but I do like its tone and its approach.