ON THE HOMOTOPY THEORY OF p-COMPLETED CLASSIFYING SPACES By Frederick R. Cohen and Ran Levi Abstract This paper is mostly a survey of work done on the subject of the title. In particular we concentrate on the study of p-completed classifying spaces of finite p-perfect groups and the associated loop spaces. We consider homological properties as well as various homotopy theoretic properties of these spaces and relate those properties to other questions in and outside of homotopy theory. A substantial number of examples, open questions and conjectures is included.