Although it is only in the very simplest cases that the order parameter of a superfluid or superconductor can be regarded literally as a Schrödinger wave function, it is quite generally “very like” one, and thinking of it in this way can often be quite helpful to one’s intuition, particularly in cases involving internal degrees of freedom. In this chapter I shall briefly sketch the basis for this point of view, starting with the very simplest case, that of a noninteracting Bose gas, and proceeding through progressively more complicated examples, to end with a Fermi superfluid with “exotic” pairing.