The papers reprinted in this book depict a research field that is poised to answer some of the fundamental questions of twentieth-century physics and astronomy: How does the sun shine? What is the dark matter? Is there new physics beyond the standard model ?This book is of interest to students as well as active researchers in the scientific areas spanned by the reprinted papers, which include physics, chemistry, astronomy, geology, and engineering. Historians of science, some of whom have already used the solar neutrino problem as a case study, will also find this collection a rich source of...