Ehhh not bad, but as Heller admits in the foreword, it is limited and he apologizes for oversights/missing "styles". The book is not as diverse as I hoped, as most 'styles' discussed are very Western/American/European-centric. I may not be the right target audience for Heller as I generally find his work speaks to a very American audience with a lot of U.S. pop culture references.
If something as silly and widely unknown as "bonehead" style can be included, why not include a style that's been popular and adapsince the 1800s like "Japonisme" that had a much wider reach, adoption/influence on Western art and design (in reference to Heller's 'pyramid scheme' model)?
Anyway, I found the descriptions of what 'style' is quite interesting. What I especially enjoyed, though, was the variety and quality of the images. Lots of visual information and source material.
Also, fun fact, I had no idea it was Napoleon Bonaparte that introduced "Egypyian style" to France i.e. the form of slab serif typefaces... interesting.