Happiness is our natural state, for each of us and for humanity as a whole, argues John Izzo. But that happiness is being stolen by insidious mental patterns that he depicts as thieves: the thief of control, the thief of conceit, the thief of coveting, the thief of consumption, and the thief of comfort. He discovered these thieves as he sought the true source of happiness during a year-long sabbatical, walking the Camino de Santiago in Spain and living...