In this article we give an introduction to the Fock quantization of th
e Maxwell field. At the classical level, we treat the theory in both t
he covariant and canonical phase space formalisms. The approach is gen
eral since we consider arbitrary (globally-hyperbolic) space-times. Th
e Fock quantization is shown to be equivalent to the definition of a c
omplex structure on the classical phase space. As examples, we conside
r stationary space-times as well as ordinary Minkowski space-time. The
account is pedagogical in spirit and is tailored to beginning graduat
e students. The paper is self contained and is intended to fill an exi
sting gap in the literature.