Speaking at the TED Conference, famed psychologist Mihaly Czikszentmihalyi asks what's the source of happiness? And his answer comes down to this: Beyond a certain point (and it's not very far), money doesn't affect happiness too much. Rather, as his research shows, we tend to be most happy when we get immersed, almost lost in, being creative and performing at our best. It's an ecstatic state that he calls "flow." The video runs about 19 minutes, and is well worth your time. Some book titles worth checking out include: Flow: The Psychology of Optimal Experience or Finding Flow: The Psychology of Engagement with Everyday Life.