  In quantum field theory, physicists routinely use "normal ordering" of
operators, which just amounts to shuffling all creation operators to the left.
Potentially confusing, then, is the occurrence in the literature of
normal-ordered functions, sometimes called "Wick transforms". We aim to
introduce the reader to some basic results and ideas around this theme, if not
the mathematical subtleties; our intended audience are instructors who want to
add something to their quantum field theory course, or researchers who are
interested but not specialists in mathematical physics. For rigorous proofs and
careful mathematical discussions we only give references.
