Picked up this book after a leadership training class in October. I was a bit skeptical at first, but its more of a research psychology book than a self help book. His essential theory is that Achievement = Talent + Desire + Optimism, and that optimism can be learned by changing explainatory style (how you explain both positive and negative events).
The defining characteristic of pessimists is that they tend to believe that bad events will last a long time, will undermine everything they do, and are their own fault.
The optimists think about the misfortune in the opposite way. They tend to believe that defeat is just a temporary setback, that its causes are confined to one case.
Seligman’s research spans from child development, to politics, to team sports — so it makes for an interesting read for a wide audience.