A Dog's Purpose Book 🐶 By W. Bruce Cameron A Dog's Purpose--the #1 New York Times bestseller and major motion picture Based on the beloved bestselling novel by W. Bruce Cameron, A Dog's Purpose, from director Lasse Hallstr m (The Cider House Rules, Dear John, The 100-Foot Journey), shares the soulful and surprising story of one devoted dog (voiced by Josh Gad) who finds the meaning of his own existence through the lives of the humans he teaches to laugh and love.