St. Martin-A Dog's Purpose. Heartwarming, insightful, and often laugh-out-loud funny. This book is not only the emotional story of a dog's many lives, but also a dog's-eye commentary on human relationships and the unbreakable bonds between man's best friend. Author: W. Bruce Cameron. Softcover: 333 pages. ISBN: 978-0-7653-3034-5. Imported.