This volume comprises selected lectures presented in the Ninth Course of the International School ofCosmic-Ray Astrophysics held at the Ettore Majorana Centre in Erice, Sicily, May 7-18,1994. Director ofthe Centre is A. Zichichi, assisted by M. Zaini. Director ofthe School is M. M. Shapiro. 1. P. Wefel was co-director of the Ninth Course, which was also a NATO Advanced Study Institute (ASI), and NATO support is gratefully acknowledged. Devoted to problems and prospects in high-energy astrophysics and cosmology, the major areas explored in this course were: gamma-ray, X-ray, and neutrino astronomies; cosmic rays; pulsars and supernova remnants; and cosmology, as well as cosmogony. Among the principal developments in gamma-ray astrophysics were those generated by the Compton Gamma Ray Observatory. Cosmic neutrinos at MeV energies, i.e., those from the sun and from Supernova 1987a, were discussed, as well as neutrino masses in astrophysics. The source composition ofcosmic rays, and extensive air shower experiments, received special attention. The early universe according to COBE data, and as viewed by theorists ofcosmology, was reviewed. Finally, the connections with particle physics occasioned a timely description ofthe Standard Model ofelementary particles.