As a medical practitioner who is not versed with the intricate details of quantum mechanics and relativitiy (let alone string theory), I have been waiting for some time to read a book which explains in laymen terms, yet not too simplistically, the most recent attempts to formulate a Theory of Everything (TOE). I have enjoyed many books on related topics by people such as Paul Davies, Stephen Hawking, Murry Gell-Mann, Timothy Ferris, John Gribbin, Michio Kaku and others, however I desperately wanted to extend my knowledge to String Theory and its applications.
I picked up Brian Green's book with alacrity and wasn't disappointed. This book explains in sufficient but not too laborious detail the most recent advances in String/M Theory. Overall, the book is well structured and illuminating. Pitching with the right amount of detail and employing cogent analogies makes it a very easy read for a layperson. The one thing I would have liked, however, was a little bit of mathematical detail although I don't honestly know if this is feasible given the breadth of the topic.
Certainly a must read for anyone intersted in keeping abreast of the physics frontier, albeit it in an amateur way.