In this review, the production and detection of a wide range of unstable free-radical species under molecular beam conditions are described. The use of such molecular beam methods to study the photodissociation and inelastic and reactive scattering of free radicals in recent years is reviewed. A selection of the many experiments on the photodissociation of radicals that have been performed recently using molecular beam conditions is described to illustrate the range and scope of such experiments. For the comparatively smaller fields of free-radical inelastic and reactive scattering studied using molecular beam techniques, a comprehensive review is presented. In all cases, the experimental results are interpreted and discussed with reference to recent related theoretical calculations on the electronic structure and dynamics for the systems. A particular aim is to illustrate how the observed features of the experiments are related to information on the topography of and the couplings between the appropriate potential energy surfaces and the associated dynamics.