This is the third and last show on Kip Thorn'es book, Black Holes and Time Warps. This show discusses the contributions of British physicist Roger Penrose,who introduced the branch of mathematics of Topology into the study of black holes. Topology proved to be a powerful new tool in helping develop a theory on the formation and final stages of the development of black holes and singularities. Before Penrose's contribution, physicists were divided into a number of schools concerning black holes and singularities, but none of the theories proved satisfactory. Topology revolutionized black hole theory, and allowed scientists to forge ahead and develop final theories concerning black holes and their formation, that all physicists could agree on.