> Most non-fiction books revolve around a few central ideas. That only applies to business, popular history, popular psychology, self-help, etc. books written

> Most non-fiction books revolve around a few central ideas. That only applies to business, popular history, popular psychology, self-help, etc. books written for the mass market. Not surprisingly most of them are garbage and frequently wrong. Malcolm Gladwell's books are probably the most well known in this geanra and IMO are garbage. As soon as you start reading serious non-fiction (mathematics, psychology, philosophy) summaries just do not work. The "book about the book" in fact tends to be much longer in length (good examples: anything on Wittgenstein, anything on Galois theory)