 
Summary: 6884 J. Phys. Chem. 1989, 93. 68846887
he was named a Distinguished Professor of Physical Science. Bob
retired from the University of Maryland in 1988 and joined the
Chemical Physics Division of the National Institutes of Health.
The first scientific article by Zwanzig appeared nearly 40 years
ago. Over the years, Bob has produced numerous fundamental
papers in diverse areas of statistical mechanics. The clear and
concise way in which these papers are written is a testimony to
Bob's deep physical insight into complicated problems. Often his
solutions to problems have become the basis of new and widely
used techniques in statistical mechanics. The two most notable
examples are his introduction of the projection operator technique
into nonequilibrium statistical mechanics and his use of the
perturbation theory to treat problems in the theory of liquids.
The projection operator method, which Bob introduced in 1960,
has been the cornerstone in the statistical mechanics of irreversible
processes. In this work Bob presented, for the first time, a for
malism to calculate dynamic physical quantities without resort
to perturbation theory. In the three decades that have passed since
this work appeared, the number of applications of this method
