Despite the voluminous literature on the famous trans-continental trek of 1804-06, Paton, a retired cardiac surgeon and wilderness medicine specialist, has seen only one study of its medical aspects, and that was a 1979 technical account. Here he examines for general readers the diagnosis and treatment of the three major crises: the death of Sergeant Floyd, the illness of Sacagawea, and the gunshot wound of Lewis. He also considers the effect on the expedition if either Sacagewea or Lewis had died. Annotation c. Book News, Inc., Portland, OR (booknews.com)