1. Those who wish to learn more about the early life and work of Viktor Hamburger should read the address in his honor by his friend Johannes Holtfreter (called Hans in the present narrative) in ?The Emergence of Order in Developing Systems,? Symposia of the Society for Developmental Biology, M. Locke, ed., 27 (1968), pp. ix?xx. A more recent account is to be found in R. Levi-Montalcini, ?One of Spemann's Pupils,? in Studies in Developmental Neurobiology; Essays in Honor of Vitor Hamburger, ed. M. Cowan (Oxford: Oxford University Press, 1982). pp. 22?243.