Joining Together - Group Theory and Group Dynamics by Johnson and Johnson 10th Edition.

I borrowed this book and read the first 20 pages.  I had a lightbulb moment about staff management.  I continued to read on another 80 pages and had several of my beliefs validated.  I had to give the book back.  I am now waiting on my copy to arrive so I can re-read those pages, and read the next several hundred pages.

Thoroughly recommended it.