More than twenty years ago I gave a course on Fourier Integral Op-
erators at the Catholic University of Nijmegen (1970-71) from which a
set of lecture notes were written up; the Courant Institute of
Mathematical Sciences in New York distributed these notes for many
years, but they be- came increasingly difficult to obtain. The current
text is essentially a nicely TeXed version of those notes with some
minor additions (e.g., figures) and corrections. Apparently an
attractive aspect of our approach to Fourier Integral Operators was its
introduction to symplectic differential geometry, the basic facts of
which are needed for making the step from the local definitions to the
global calculus. A first example of the latter is the definition of the
wave front set of a distribution in terms of testing with oscillatory
functions. This is obviously coordinate-invariant and automatically
realizes the wave front set as a subset of the cotangent bundle, the
symplectic manifold in which the global calculus takes place.