The 1986 Seminar on Stochastic Processes was held at the University of Virginia, Charlottesville, in March. It was the sixth seminar in a continuing series of meetings which provide opportunities for researchers to discuss current work in stochastic processes in an informal atmosphere. Previous seminars were held at Northwestern University, Evanston and the University of Florida, Gainesville. The participants' enthusiasm and interest have resulted in stimulating and successful seminars. We thank them for it, and we also thank those participants who have permitted us to publish their research here. The seminar was made possible through the generous support of the Office of Naval Research (Contract # A86-4633-P) and the University of Virginia. We are grateful for their support. The participants were welcomed to Virginia by S. J. Taylor, whose store of energy and organizing talent resulted in a wonderful reunion of researchers. We extend to him our warmest appreciation for his efforts; his hospitality makes us hope that we can someday return to Virginia for another conference. J. <.