"e of the reasons for all the F ASEB Societies to meet yearly is the possibility O to interrelate recent progress in diverse areas of research. The F ASEB Conferences have been organized to promote such interdisciplinary approaches. They center around a basic theme with the aim of discussing active research, in­ cluding widely divergent approaches, towards a better understanding of a general biological phenomenon. Because of the mounting interest in the subject of aging and development, this has been chosen as the theme for this year's symposia. We have necessarily been limited in the number of topics that could be covered. In our choice we have attempted to' select those facets of the main subject which at this time are gen­ erating active research interest among our membership. We have included invited speakers from abroad, such as Drs. Goldstein, Liew and Miller from Canada and Drs. Wolpert, Holliday and Williamson from England. I am sorry to say that the two speakers that we had invited from Russia, Dr. Frolkis, and from Czechoslovakia, Dr. Sterzl, were unable to attend.

This book meets the demand of a recent surge of interest in germinal centers, the foci of antigen-induced, rapidly proliferating B lymphocytes, representing sites in mammalian lymphoid tissue where memory B cells are generated. Various aspects of the generation of germinal centers, the somatic hypermutation process and the cellular interactions involved in the selection process are discussed in detail. A chapter on germinal center-derived lymphomas completes the treatment.

"e of the reasons for all the F ASEB Societies to meet yearly is the possibility O to interrelate recent progress in diverse areas of research. The F ASEB Conferences have been organized to promote such interdisciplinary approaches. They center around a basic theme with the aim of discussing active research, in­ cluding widely divergent approaches, towards a better understanding of a general biological phenomenon. Because of the mounting interest in the subject of aging and development, this has been chosen as the theme for this year's symposia. We have necessarily been limited in the number of topics that could be covered. In our choice we have attempted to' select those facets of the main subject which at this time are gen­ erating active research interest among our membership. We have included invited speakers from abroad, such as Drs. Goldstein, Liew and Miller from Canada and Drs. Wolpert, Holliday and Williamson from England. I am sorry to say that the two speakers that we had invited from Russia, Dr. Frolkis, and from Czechoslovakia, Dr. Sterzl, were unable to attend.

This book meets the demand of a recent surge of interest in germinal centers, the foci of antigen-induced, rapidly proliferating B lymphocytes, representing sites in mammalian lymphoid tissue where memory B cells are generated. Various aspects of the generation of germinal centers, the somatic hypermutation process and the cellular interactions involved in the selection process are discussed in detail. A chapter on germinal center-derived lymphomas completes the treatment.