Session I Physiology of Meristems.- On the Initiation of Organization in the Root Apex.- Mitotic Cycle Regulation in the Meristem of Cultured Roots: The Principal Control Point Hypothesis.- Meristematic Activity in Relation to Wound Xylem Differentiation.- Session II Structural Dynamics of Meristems.- A Morphogeneticist's View of Correlative Inhibition in the Shoot.- The Surface "Histogen" of Living Shoot Apices.- On Determination of Leaf Primordia in Osmunda Cinnamomea L.- Mechanisms of Perception and Patterns of Organisation in Root Caps.- The Control of Cell Proliferation within Root Meristems.- Session III Radiation as a Tool to Investigate Meristems.- Morphogenetic Aspects of the Development of Meristems in Seed Embryos.- Morphogenesis of Primordia of Lateral Roots.- Cell Division, Development, and Radiation Injury.- Shoot Dry Weight of the Soybean Seedling Following Gamma Irradiation: Effects of Exposure, Exposure Rate, and Split Exposure.- Session IV Meristems as Radiobiological Test Systems.- Some Problems of Chromosomal Aberration Studies in Meristems.- Seed Meristems as Radiobiological Test Systems.- Contributions of Seed Meristems to Radiobiology.- Radiation Probes of Maize Meristems.- Session V General Discussion and Synthesis; Conclusions.- The Conference in Retrospect.- Author Index.

These proceedings are composed of three parts: 1) the indi­ vidual papers, 2) their discussions, and 3) a retrospective summa­ tion of the meeting's deliberations. If we were to suggest a start­ ing place for reading it would probably be the summation --it at­ tempts to place the various papers and discussions into a general context and to point out relevant ideas of current knowledge and of potentially useful avenues for further research. The papers and discussions deal more specifically with the indiviaual topics. It is hoped that the tone and tenor of the meeting are some­ what reflected in its proceedings. The emphasis today in biological research is quite "ecumenical" in outlook in that often techniques and conclusions from one discipline have relevance and applicability to another. For example, the elucidation of the DNA synthetic stage during interphase was first accomplished with botanical material; this technique has since had a broad and significant role in medical research. Also, the pioneering and now classical studies regarding the effects of ionizing radiation on plant chromosomes were, and still are, the foundation for studying mammalian chromosomes: it re­ quired only the discovery of a hypotonic medium to achieve spreading of them so that similar types of analyses were possible. Plants and plant cells have many unique features which allow them to be useful either for the study of specific botanical problems, or for studying broad biological principles.