This collection of articles is dedicated to Frank Spitzer on the occasion of his 65th birthday.
The articles written by a group of his friends colleagues former students and coauthors are
intended to demonstrate the major influence Frank has had on probability theory for the last 30
years and most likely will have for many years to come. Frank has always liked new phenomena
clean formulations and elegant proofs. He has created or opened up several research areas and
it is not surprising that many people are still working out the consequences of his inventions.
By way of introduction we have reprinted some of Frank's seminal articles so that the reader
can easily see for himself the point of origin for much of the research presented here. These
articles of Frank's deal with properties of Brownian motion fluctuation theory and potential
theory for random walks and of course interacting particle systems. The last area was
started by Frank as part of the general resurgence of treating problems of statistical
mechanics with rigorous probabilistic tools.
