I picked this up after reading about it on the Independent's top sports books of 2008 and recognising the author's name; also, I'm studying the history of London and one module I'm thinking of doing next is on the "Olympic City". So this sounded like it could be an interesting book.
It's clearly a well researched and well written book, with lots of information related in a fairly anecdotal manner, and a comprehensive index and 4 page bibliography (the references aren't cited in relevant sections of the text, but this isn't a textbook after all). I found chapters 11 and 12 on women athletes and the marathon (respectively) quite interesting, as well as the "custom" of shouting "God save the Queen!" at the 24 mile marker. The author makes the convincing point that this was the first major modern Olympics, whereas previous Olympics were largely domestic events and not much more than cursory additions to world fairs, and had a much higher level of international participation - with all the risks of misunderstanding that this could (and did) involve. Perhaps this is what "Cautionary Tale" refers to in the subtitle.
It was well worth the pleasant Sunday afternoon I spent reading it.