By Barb Shelly, Kansas City Star editorial page columnist

Lots of tributes today in honor of Nelson Mandela's 90th birthday.

Mandela has lived long enough to have seen his life thoroughly examined by biographers, friendly and otherwise.

But is there any doubt that he is one of the towering statesmen of the ages? I don't think so. And can anyone remember a better news day than Feb. 11, 1990, when Mandela walked out of the Victor-Verster Prison in Paarl, South Africa, after a 27-year imprisonment? I surely cannot.

The best book about Mandella's life is the one he wrote, Long Walk to Freedom. What impressed me most was his retelling of measures he took to make sure his years in prison counted for something. He studied, followed a rigorous fitness routine, even grew gardens. The last years were spent in diplomatic bargaining with the nation's rulers, who knew that the racist apartheid government was unsustainable.

South Africa has a lot of problems, but also a lot of hope. The fact that it didn't dissolve into civil war and anarchy after the demise of apartheid can be largely credited to Mandela's leadership.