The subject of this review is the field of intense pulsed ion beam generation and its potential application to fusion research. Considerable progress has been made in the past six years. Power levels of the order of 1000 MW/cm2 have been obtained for pulse-lengths from 10−8 to 10−6 s. Light-ion beams with currents approaching 1 MA and energies exceeding 1 MeV have been produced. The first half of the paper treats the physics and technology of beam generation. Following a unified discussion of the theory of ion injectors, experimental work since 1973 is reviewed. Diagnostic techniques appropriate to high-flux ion beams are summarized. The general problem of high-current ion beam transport in vacuum and through plasmas is also considered. The second part of the paper is devoted to applications to fusion research. Applications in both magnetic confinement and inertial confinement fusion are considered. Intense ion beams have a number of features which make them ideally suited as inertial fusion drivers. Discussions are given of the physics of inertial fusion targets, options for ion beam production, experiments on light-ion beam focusing, and high-current multi-stage accelerators.