International Series of Monographs in Natural Philosophy, Volume 5: Weak Interaction of Elementary Particles focuses on the composition, properties, and reactions of elementary particles and high energies. The book first discusses elementary particles. Concerns include isotopic invariance in the Sakata model; conservation of fundamental particles; scheme of isomultiplets in the Sakata model; universal, unitary-symmetric strong interaction; and universal weak interaction. The text also focuses on spinors, amplitudes, and currents. Wave function, calculation of traces, five bilinear covariants, and electromagnetic interaction are explained. The text also discusses charge conjugation, inversion of coordinates, and time reversal; weak interaction between leptons; and leptonic decays of strongly interacting particles. The text also explains strangeness conserving leptonic decays. Conservation of the vector current; electromagnetic properties of protons and neutrons; vector coupling constant; and relationships between weak and electronic form factors are underscored. The book also discusses weak interaction at small distances. Intermediate bosons, local four-fermion interactions, and statement of the problem are explained. The text is a vital reference for readers interested in the composition, properties, and reactions of elementary particles and high energies.