This volume covers a number of areas of high energy astrophysics, focusing on the current status/understanding of the field, outstanding problems to be resolved and, in many cases, new experiments that will be providing some answers after the turn of the century. Featured are the following topics: high energy frontier, including the enigmatic observations of events beyond the cut-off energy; gamma ray bursts — local and cosmological models; high energy astrophysical neutrinos; cosmic ray matter and antimatter; solar system astrophysics; and galactic physics. The discussion is suitable for the nonexpert and expert alike.