  Students of quantum mechanics encounter discrete quantum numbers in a
somewhat incoherent and bewildering number of ways. For each physical system
studied, quantum numbers seem to be introduced in its own specific way, some
enumerating from 1 and others from 0, without a common uniting thread. This
essay presents a point of view that builds on dimensions, boundary conditions
and various inputs that, while known, are often not brought together to present
a simple, consistent picture. At the same time, some surprisingly sophisticated
connections are also made.
