The academic year 1987-88 was designated as an Emphasis Year in Al-
gebraic Topology at Northwestern University. Supported by funds from the
National Science Foundation and Northwestern, visitors from around the world
came together throughout the year to discuss current developments. During the
period March 21-24, 1988 a conference was held which attracted over 110 par-
ticipants. Many of the plenary lectures were expository in nature, designed to
expose current trends. This volume contains papers which were either presented
or solicited at the conference. All papers were refereed.
We thank Mrs. Melanie Rubin for her fine secretarial support in assembling
the volume. Several of the papers have been retyped in
and we are grateful
to Lisa Tator for her fast and efficient efforts in this regard.