Online Documentation and Tutorials
Includes the "QGIS Training Manual" (with canned data and exercises, enough for a 5-day workshop!), and the concept-oriented "A Gentle Introduction to GIS"
Great content, see menus in upper right to navigate through different common actions
Also includes excellent installation instructions
Search the U-M Library Catalog for qgis to find books, both electronic and print! Available to UM users only