The Division of Particles and Fields of the American Physical Society will hold a summer study from June 27 through July 15, 1988 devoted to high energy physics in the 1990's. The principal goal of the study is the examination and evaluation of the opportunities for high energy physics in the 1990's including the Superconducting Super Collider, new accelerator technology, non-accelerator experiments, and innovations in instrumentation and detector technology. This is the fourth in a series of studies. Previous meetings were held in 1982, 1984 and 1986.