An interesting read, but not as useful as it proposes. The book is the personal journey of the author(who much like me is a learning junkie) into realms of self-development and skill-acquisition. it begins with an manifesto against our perception of 10000 hours rule and presents a concise review of the principles and tools in rapid skill-acquisition, then dives in to illustrate those principles in acquiring several skills he had thought he could never find time to master.
Read it if you find it interesting, but you can get all you need to know about the ideas in the book from the author TEDx talk: http://tedxtalks.ted.com/video/The-First-20-Hours-How-to-Learn