In view of Professor Wendell Fleming's many fundamental contributions,
his profound influence on the mathematical and systems theory communi-
ties, his service to the profession, and his dedication to mathematics,
we have invited a number of leading experts in the fields of control,
optimiza- tion, and stochastic systems to contribute to this volume in
his honor on the occasion of his 70th birthday. These papers focus on
various aspects of stochastic analysis, control theory and optimization,
and applications. They include authoritative expositions and surveys as
well as research papers on recent and important issues. The papers are
grouped according to the following four major themes: (1) large
deviations, risk sensitive and Hoc control, (2) partial differential
equations and viscosity solutions, (3) stochastic control, filtering and
parameter esti- mation, and (4) mathematical finance and other
applications. We express our deep gratitude to all of the authors for
their invaluable contributions, and to the referees for their careful
and timely reviews. We thank Harold Kushner for having graciously agreed
to undertake the task of writing the foreword. Particular thanks go to
H. Thomas Banks for his help, advice and suggestions during the entire
preparation process, as well as for the generous support of the Center
for Research in Scientific Computation. The assistance from the
Birkhauser professional staff is also greatly appreciated.