Photo and illustration credits: Cover artwork and drawing, p. 16, by Mike Cagle; photos by Tyagan Miller, pp. 2, 4, 5, 9, 10, 15, 21; CD-ROM images from Investigating Olduvai: Archaeology of Human Origins courtesy of the Teaching and Learning Technologies Laboratory, IUB, pp. 6-7; photo of F. R. N. Gurd courtesy of the Indiana University Office of Publications, p. 8; CD-ROM images from In-Terra-Active courtesy of West Publishing Co., pp. 12-13; drawing by Noel Wheeler, p. 14; photo by Elmer Denman, Learning Resource Center, IPFW, p. 18; photo courtesy of Library and Media Services, IUE, p. 19; CD TimeSketch display image courtesy of Gary Wittlich, p. 20; CD-ROM image courtesy Linda Meyer and Carol Sternberger, p. 23; spectrograms courtesy of John Johnson, pp. 24-25.