sorry man. I've been on some week long trips to Japan, but to places like Kyoto and Sapporo, not Tokyo. So I can't offer any authoritative advice on Tokyo or books on Tokyo. If I am pressed to give book advice, I would say that in general the Lonely Planet series of guidebooks are pretty good. If you're going to live in a foreign country, then it's like you're a fish out of water. These books are written with that perspective in mind. So I would consider buying a Lonely Planet guidebook for Tokyo.
I hope you have a great time in Japan. I wish I were going too.