In your opinion, what is the best travel guide book?

I’ve always worked with Lonely Planet, which have been awesome. I’ve heard about something called a “Blue Book(?)” which is supposed to be great. I have been to China many times, and I have been recently hired for a 2nd time to be a leader out there…so I am thinking of getting the China Lonely Planet, though I’ve heard some negative things about it (poor accuracy, etc).

So in two parts – best travel book in general, and best for China?

Thx! :)