In 1876 and 1877, Captain W. P. Clark commanded a detachment of Indian scouts--including Pawnees, Shoshones, Arapahoes, Cheyennes, Crows, and Sioux--who conversed in sign language. They made requests, relayed information, and told stories with their hands, communicating in a language indispensable for quick understanding between Indians of different tribes. The scouts patiently taught Clark the sign system, which he patiently recorded in this book...