F. Reines. Introduction and preface.--Alpher, R. A. and Herman, R. Reflections on "big bang" cosmology.--Hoyle, F. and Narlikar, J. V. Conformal invariance in physics and cosmology.--Penzias, A. A. Cosmology and microwave astronomy.--Wataghin, G. On a model of the expanding universe.--Dirac, P. A. M. The variability of the gravitational constant.--Teller, E. Are the constants constant?--Fowler, W. A. New observations and old nucleocosmochronologies.--Shapiro, M. M., Silberberg, R., and Tsao, C. H. Diffusion of cosmic rays and their source composition.--Cowan, C. L. and Reines, R. Neutrino physics--prospects.--Kavanagh, R. W. Reaction rates in the proton-proton chain.--Critchfield, C. L. Analytic forms of the thermonuclear function.--Tuck, J. L. World energy reserves and some speculations on the future of nuclear fusion energy.--Longmire, C. L. Heating of charged particles by electric waves.--Yourgrau, W. and van der Merwe, A. Entropy (positive and negative), information and statistical thermodynamics.--Ulam, S. M. Gamow--and mathematics.--Delbruck, M. Out of this world.--Rosenfeld, L. Nuclear reminiscences.--Shapiro, M. M. George Gamow--an appreciation.--Alpher, R. A. and Herman, R. Memories of Gamow.