Propeller from Parallax Inc.(P8X32A-D40) books
Here are a couple:

Programming and Customizing the Multicore Propeller Microcontroller: The Official Guide

Programming the Propeller with Spin: A Beginner's Guide to Parallel Processing

The first one covers a little bit of the architecture, and then presents several projects to do; the second one concentrates on the Spin language, and how the cogs work.  Both are available in either print form or for the Kindle (which I have).

You can peek inside each of the books on the Amazon page, including the full table of contents to see what they cover.