Book Review Magnetic Resonance Imaging: A reference guide and atlas By Allen D. Elster, in collaboration with Stanley F. Handel and Arnold M. Goldman. 292 pp., illustrated. Philadelphia, J.B. Lippincott, 1986. $67.50. Practical MRI — Magnetic Resonance Imaging: A case study approach By Wilson S. Wong, Jay S. Tsuruda, Keith E. Kortman, and William G. Bradley, Jr. 451 pp., illustrated. Rockville, Md., Aspen, 1987. $74.50.