Positron annihilation: From QED to NDT a primer and a report on the 4th International Conference on Positron annihilation, held at Helsingor, Denmark, 23-26 August 1976

This report summarizes the presentations at the meeting and attempts to emphasize the highlights of the developments in the field of positron annihilation. As a preliminary to the conference review, this report also provides an introductory survey of positron physics and experimental methods for readers largely unfamiliar with positron annihilation.