A general overview of positron collision physics

I will give a brief history of the field of positronics, both experimental and theoretical, emphasizing what I consider to be the most interesting techniques, results, and processes that have been studied. These include positron and positronium scattering and annihilation in simple and complex systems, positronium formation, resonances, and bound states. Annihilation in astrophysical context will also be mentioned. It will he evident that some of the same questions that engaged the earliest workers in the field are still unanswered, but others have been brilliantly treated and largely resolved. A brief discussion about the future of the subject concludes the overview. Published by Elsevier Science B.V.