I have an account to Safari, and I've been reading a string of leadership/management books lately. Here's what I've run across.

John Baldoni's Lead by Example: 50 Ways Great Leaders Inspire Results
Baldoni provides lots of examples and case studies. I like the stories from history and business. There were some ideas that can be applied whether you directly supervise people or whether you influence others. This one is worth reading.

Joseph T. Straub's The Rookie Manager: A Guide to Surviving Your First Year in Management
Straub's work contained a lot of process and how to recommendations. Even if you aren't a first year manager, it's a good refresher. Some of the technology and processes are a little dated.

Pam Jones' Managing for Performance: Delivering Results through Others
Again, this had some good ideas for performance management and conducting reviews for others.

My favorite of the three was Baldoni's. Let me know if you have any recommendations.