Spin Waves. A. I. Akhiezer, V. G. Bar'yakhtar, and S. V. Peletminskii. Translated from the Russian by S. Chomet. S. Doniach, translation editor. North-Hol-land, Amsterdam; Interscience (Wiley), New York, 1968. viii + 369 pp., illus. $21.50. North-Holland Series in Low Temperature Physics, vol. 1