  We examine the extent to which the action for the membrane of M-theory (the
eleven-dimensional construct which underlies and unifies all of the known
string theories) simplifies in the so-called Open Membrane (OM) limit, a limit
which lies at the root of the various manifestations of noncommutativity in the
string context. In order for the discussion to be relatively self-contained, we
start out by reviewing why the strings of ten-dimensional string theory are in
fact membranes (M2-branes) living in eleven dimensions. After that, we recall
the definition of OM theory, as well as the arguments showing that it is part
of a larger, eleven-dimensional structure known as Galilean or Wrapped M2-brane
(WM2) theory. WM2 theory is a rich theoretical construct which is interesting
for several reasons, in particular because it is essentially a toy model of
M-theory. We then proceed to deduce a membrane action for OM/WM2 theory, and
spell out its implications for the four different types of M2-branes one can
consider in this setting. For two of these types, the action in question can be
simplified by gauge-fixing to a form which implies a discrete membrane
spectrum. The boundary conditions for the remaining two cases do not allow this
same gauge choice, and so their dynamics remain to be unraveled.
