  Quantum field theory has formed the conceptual framework of most of physics
for more than sixty years. It incorporates a complete revision of our
conception of the nature of matter and existence itself. Yet it is rarely
taught, or even mentioned, in introductory physics---from high school, college,
and university survey courses through upper-division "modern physics" courses.
This omission is not necessary: This paper describes an approach through which
the fundamental concepts and consequent insights of quantum field theory can be
grasped, building upon familiar notions from classical and quantum mechanics.
