The 7 Habits of Highly Effective People (Steven R. Covey)
Honestly speaking, I’ve been reading this book for about a year. Making pauses for weeks, returning back and rethinking. It just contains so much information and inspiration that I had to stop and think about everything I read.
It’s very difficult to apply all the principles described there and I’m sure it’s not even necessary. Everybody takes what he or she needs. But once taken, you never regret.