A timely addition to the literature, this volume contains authoritative reviews of three important areas in the physics of elementary particles. Sam B. Treiman, in "Current Algebra and PCAC," reviews the present state of the weak interactions. In "Field Theoretic Investigations in Current Algebra," Roman Jackiw deals with recent developments in current algebra and its applications, giving particular attention to anomalies. David J. Gross covers the high energy inelastic lepton-hadron scattering in his paper, "The High Energy Behavior of Weak and Electromagnetic Interactions." Originally published in 1972. The uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.