There are a lot of good books about coffee, but none is more comprehensive and authoritative than Mark Pendergrast's "Uncommon Grounds: The History of Coffee and How it Transformed the World."

Pendergrast has updated the 1999 book with a second edition that came out today. In its introduction, the new edition corrects the widespread belief published in the earlier edition that coffee is the world's second most valuable exported legal commodity after oil; it is the fourth most valuable agricultural commodity. The author detailed his research on that matter at Entrepreneur.com last year.

He writes about the coffee crisis of 1999 to 2004, and says "Such a humanitarian disaster simply extended the boom-bust cycle that began in the late nineteenth century and will continue in the future, unless we somehow learn more from the distant and recent past."

The most interesting part of the new book is its last chapter, still called "Final Grounds," but this time packed with new thoughts on Starbucks, Fair Trade, rock-star baristas and the threat of global warming.

If 400 pages is a little too much coffee reading for you, there's always Seattle Magazine's coffee guide, out this month with lists of iconic shops, independent shops, coffee carts and corporate giants (Starbucks and Tully's) and other information.