Mesoamerica after the Decline of teotihuacan, A.D. 700-900. Richard A. Diehl and Janet Catherine Berlo, Eds. Dumbarton Oaks Research Library and Collection, Washington, DC, 1989. viii, 244 pp., illus. $60. Based on a seminar, June 1984; Tula of the Toltecs. Excavations and Survey. Dan M. Healan, Ed. University of Iowa Press, Iowa City. 1989. xii, 301 pp., illus., + charts and diskette. $45.