Here's a pretty interesting book from Nerdcore (those of the entertaining calendars). Joe Ledbetter's Sketchbook is the first release in their Sketchbook Series. It gives you an intimate look at what went into creating some of Ledbetter's most beloved characters.
At 184 pages, you'll see vinyl figure mockups, illustration concepts, rough compositions for famous paintings, to-do lists, random phone numbers, etc. The book will ship this coming October and will sell for $25 apiece.