The objective of the meeting was to provide a companion meeting to the ''First Symposium on Accelerator Radiation Dosimetry and Experience'' which was held November 3-5, 1965, at the Brookhaven National Laboratory. This first symposium was limited in scope to an intensified discussion of dosimetry techniques. The biology which is associated with high energy radiation was specifically excluded, since it was the original plan to hold a second symposium devoted entirely to biology. Thus the present Symposium was a sequel to the first and they were inseparable in their objectives. Since those attending the BNL Symposium were almost entirely health physicists with a background in physical science and actively engaged in the solution of radiation protection problems at high energy accelerators, it was felt that it would be necessary to begin the BID Symposium with a general review session on radiation biology, in order to provide a biological background for the proper understanding of the later sessions. This first session was arranged to give the health physicist a meaningful transition from fundamental radiobiological considerations to current new research activities in high energy biology. In our opinion, and also based on the comments of several of those attending these objectives were quite well attained. The talks by Bond, Robertson, Brustad, Wolff, and Patt were quite exhaustive as an introduction to the several areas of specialization in radiobiology. The overall purpose of the meeting was of course to inform the health physicists about the state of knowledge in advanced biological research as it might apply to their problems. It has often been said that it takes a long time for laboratory findings to be applied in practical situations, but this is certainly not true in radiobiology. Through this conference and others like it, the most recent understanding of high energy radiobiology is available to the practicing health physicist and is probably used fairly effectively. In addition, much of this material applies equally well to reactor and space radiation problems, and some of the participants were from these areas as well.