NO ONE TRAVELS QUITE LIKE RICHARD GRANT and, really, no one should. In his last book, the adventure classic “God’s Middle Finger, “he narrowly escaped death in Mexico’s lawless Sierra Madre. Now, Grant has plunged with his trademark recklessness, wit, and curiosity into East Africa. Setting out to make the first descent of an unexplored river in Tanzania, he gets waylaid in Zanzibar by thieves, whores, and a charismatic former golf pro before crossing the Indian Ocean in a rickety cargo boat. And then the real adventure begins. Known to local tribes as “the river of bad spirits,” the Malagarasi River is a daunting adversary even with a heavily armed Tanzanian crew as travel companions. Dodging bullets, hippos, and crocodiles, Grant finally emerges in war-torn Burundi, where he befriends some ethnic street gangsters and trails a notorious man-eating crocodile known as Gustave. He concludes his journey by interviewing the dictatorial president of Rwanda and visiting the true source of the Nile. Gripping, illuminating, sometimes harrowing, often hilarious, “Crazy River “is a brilliantly rendered account of a modern-day exploration of Africa, and the unraveling of Grant’s peeled, battered mind as he tries to take it all in.