Ghanaian economist George Ayittey was a voice in the wilderness for many years, crying out against the corruption and complacency that -- more than any other factor, he believes -- are the bedrock problems of many troubled Africa states. "We call our governments vampire states, which suck the economic vitality out of the people," he says.

His influential book Africa Unchained has helped unleash a new wave of activism and optimism -- especially in the African blogosphere, where his notion of cheetahs-versus-hippos has become a standard shorthand. The "Cheetah Generation," he says, is a "new breed of Africans," taking their futures into their own hands, instead of waiting for politicians to empower them. (He compares them to the previous "Hippo Generation," who are lazily stuck complaining about colonialism, yet doing nothing to change the status quo.)

Ayittey is a Distinguished Economist in Residence at American University in Washington, DC.