Euglena

attempted to cover metabolic matters already reviewed in Volumes I and II of The Biochemistry and Physiology of Protozoa (eds. Lwoff and Lwoff and Hutner). To those interested in the broader aspects of photo­ synthesis and photoreception reference is made to Photosynthesis and Related Processes Volume I and parts I and 2 of Volume II by E. Rabinowitch; the Brookhaven Symposium on The Photochemical Ap­ paratus: Its Structure and Function (1959); the New York Academy of Sciences conference on Photoreception (1958) and to the many recent symposia reviews and current journal literature. This book is primarily concerned with the use of Euglena in study­ ing photoreception; it is also hoped that biologists biochemists and biophysicists will find in Euglena a remarkably versatile research tool for attacking some of their problems. I would like to thank Drs. S. H. Hutner and L. Provasoli of the Haskins Laboratories for introducing me to Euglena as an exceptional experimental animal as well as for many stimulating discussions and continued enthusiasm. I am indebted to Drs. G. E. Palade and K. R.