Revided and updated. Ambitious in scope, immensely readable -- and as big as a doorstop -- Martin Meredith's overview of the tumult, horrors and strides made in Africa since independence is invaluable. A veteran newspaperman and historian, Meredith has written biographies of Mandela and Mugabe. He is particularly strong in sketching the personalities and events in South and East Africa.  (AFR154, $21.99)