Books

There are several books about networks, some of them are relevant for trust metrics.

Networks

 * Six Degrees
 * Linked
 * Nexus

Crowds

 * Wisdom of Crowds

Fiction
freely downloadable:
 * Down and Out in the Magic Kingdom, http://craphound.com/down/
 * Eastern Standard Tribe, http://craphound.com/est/
 * A Place So Foreign and Eight More, http://craphound.com/place/

Good sources of books

 * Creative Commons books