Diversification is protection against ignorance. It makes little sense if you know what you are doing. - Warren Buffett

My partner, Charlie, says that there's only three ways that a smart person can go broke: liquor, ladies and leverage.

Loss of focus is what most worries Charlie and me when we contemplate investing in businesses that in general look outstanding. All too often, we’ve seen value stagnate in the presence of hubris or of boredom that caused the attention of managers to wander.

There is no tougher job in corporate America than running an airline: Despite the huge amounts of equity capital that have been injected into it, the industry, in aggregate, has posted a net loss since its birth after Kitty Hawk. Airline managers need brains, guts, and experience — and