Buffett: The Making of an American Capitalist (1995) by Roger Lowenstein
This biography provides an intriguing and thorough look into the personal and business life of famed investor Warren Buffett. It reveals aspects of his personality and childhood that laid the foundation for his investing career and details the major events and decisions that led to his successes. The book is well-written and very readable, with good transitions between various facets of Buffett's life and seamless integration of historical facts, behind-the-scenes stories, and quotes into a coherent narrative.
Note: I read this book in December 2011.