It's great to read an adventure story, a detective, or a novel once it's summer. However, if you feel you'd like to catch up on culture, leadership, and change here's my list of favorite non-fiction books at this point.
On positive leadership, change, and culture
Arbinger Institute, Leadership and Self Deception - Getting out of the box (Berrett-Koehler Publishers; 2nd edition, 2015)
Kim Cameron, Positive Leadership - Strategies for extraordinary performance, (Berrett-Koehler Publishers, 2008)