'First, Break All the Rules' is a great read. For new managers, I highly reccomend 'The First 90 Days'

Remember not to just accept everything in these books. They should be read with the expectation that you will have to pull out the useful pieces that are relevant to you.

Peopleware and Slack by Tom DeMarco are must-reads. I re-read Peopleware once every few years. I also liked Delivering Happiness (by @zappos) and Tribal Leadership, although they are more about organizations than management per se.