The recent proliferation of literature on the Regge pole model has made it evident that a general review of the model is needed. This paper summarizes work done in the field prior to October 1968. It reviews the types of singularities thought to exist in the complex angular-momentum plane, the symmetries of Regge amplitudes and trajectories with special emphasis on four-dimensional symmetry associated with zero momentum transfer, properties of both meson and baryon trajectories, predictions of the model, and suggested experimental tests of various assumptions made in the model. The paper is written for the general reader with an interest in the field and for those in the field interested in areas in which they are not directly involved. There is as little use of mathematics as possible, with emphasis essentially on the results and conclusions of recent papers.

DOI:https://doi.org/10.1103/RevModPhys.41.669