This book comprises a broad selection of expository articles that were written in conjunction with an international conference held to honor F.W. Gehring on the occasion of his 70th birthday. The objective of both the symposium and the present volume was to survey a wide array of topics related to Gehring's fundamental research in the field of quasiconformal mappings, emphasizing the relation of these mappings to other areas of analysis. The book begins with a short biographical sketch and an overview of Gehring's mathematical achievements, including a complete list of his publications. This is followed by Olli Lehto's account of Gehring's career-long involvement with the Finnish mathematical community and his role in the evolution of the Finnish school of quasiconformal mapping. The remaining articles, written by prominent authorities in diverse branches of analysis, are arranged alphabetically. The principal speakers at the symposium were: Astala, Baernstein Earle, Jones, Kra, Lehto, Martin, Sullivan, and Va"isa"la". Other individuals, some unable to attend the conference, were invited to contribute articles to the volume, which should give readers new insights into numerous aspects of quasiconformal mappings and their applications to other fields of mathematical analysis. Friends and colleagues of Professor Gehring will be especially interested in the personal accounts of his mathematical career and the descriptions of his many important research contributions.