The authors are Jim Loehr and Tony Schwartz. They do consulting work for corporate executives, professional athletes, and others who are looking to increase productivity in their lives and occupations, but the principles in the book can apply anyone.
The book first focused on the importance of nutrition, exercise, stress reduction, and other activities that impact one's productivity, but it later addressed mental, social, and spiritual items and how they can create renewal. They use many case studies examples and explain how their recommendations can help people overcome the bad habits that are draining their productivity and happiness.
I think that this book would appeal to anyone who is trying to figure out how to fit more into their day or to accomplish more and improve their performance. I also think you will live a healthier lifestyle by following many of the principles it promotes.