Book Review Fetal and Neonatal Physiology Edited by Richard A. Polin and William W. Fox. 1884 pp. in two volumes, illustrated. Philadelphia, W.B. Saunders, 1992. $300. ISBN 0–7216–2963–6 . Schaffer and Avery's Diseases of the Newborn Sixth edition. Edited by H. William Taeusch, Roberta A. Ballard, and Mary Ellen Avery. 1115 pp., illustrated. Philadelphia, W.B. Saunders, 1991. $125. ISBN 0–7216–2476–6 . Primary Care of the Preterm Infant By Judy C. Bernbaum and Marsha Hoffman-Williamson, with Jo Ann D'Agostino, Susan Friedman, and Anne Farran; Benjamin K. Silverman, consulting editor. 344 pp., illustrated. St. Louis, Mosby—Year Book, 1991. $34.95. ISBN 0–8151–0737–4 .