Are you looking for short books that broaden your horizon? Two quick reads that I've finished recently are "Tao Te Ching" by Lao Tzu and "It Doesn't Have to Be Crazy at Work" by David Heinemeier Hansson and Jason Fried.
"Tao Te Ching" is a collection of philosophical thoughts. It deals with issues of trust, flexibility, and the search for wisdom. For a book that's almost 2500 years old, it felt very fresh and timely.
"It Doesn't Have to Be Crazy at Work" deals with a more direct approach. The authors, founders of a company called Basecamp, share their observations on how to make the work feel less like a burden. They describe how they care for the health (physical and mental) of their employees. How they keep the teams small so it is easier to communicate. And how they value commitment more than consensus.
All the suggested solutions come from their own experience and are often results of countless experiments. These solutions may not work for you, but they are interesting to learn from.