NATIVES & STRANGERS by Louisa Dawkins (Houghton Mifflin: $18.95). A sweeping African saga set in Tanganyika and Kenya from the '50s to the '70s, is the fascinating story of Marietta Hamilton's quest for identity in post-Colonial times. It opens with her restless mother, a widow who manages guest-houses for British visitors, leaving for a holiday in England. The remainder of Marietta's "family" consists of Justin, the black caretaker to whom her father entrusted his unborn child, and Violet, Justin's daughter. The two girls grew up under the same roof, shared the same bed, and Marietta considers Violet her true sister. While her mother is in England, Marietta goes with Justin and Violet to their home in Galana where Justin's tender, fatherly concern for Marietta causes "sibling" jealously in Violet. These finely rendered relationships interweave a gripping richly plotted story. A second-generation white settler, Marietta considers herself a "native" of Africa, but as a young adult realizes she's considered a "stranger" by a black majority slowly acquiring power. Through the magic of Africa's mountains and plains, and an authentic cast of black and white characters that saturate Marietta's life, her marriage to a white hunter, and her deep love for a black politician, Louisa Dawkins' accomplished novel captivates and brilliantly introduces the complex changing society of Africa in post-Colonial times.