The notes contained in this volume are based on the 1964 Brandeis summer lectures of four specialists in field
theory and elementary particles. Professor Lichtenberg gave
a one-week introductory survey of particle phenomenology.
He has kindly updated the experimental facts in his survey
to January, 1965. The contributions of the three longer-
term lecturers are built around their own recent research in
topics at the forefront of current interest. Professor
Johnson lectured for three weeks on "asymptotic" quantum
electrodynamics in terms of the new methods developed with
his collaborators. Professor Schwinger gave an account of
his current investigations of the properties of particles.
Particular emphasis is laid on field theory as a guiding
principle. Professor Weinberg's six weeks series of lec-
tures were divided between two topics - the problem of
elementary and composite particles, and the theory of mass-
less particles - which appear as separate sections of this
volume.