  We review recent progress in formulating the worldvolume theory of M2-branes
using the Nambu bracket. Although it is generally agreed that this formulation
should be replaced by another using the superconformal Chern-Simons theory, we
try to pursue a possible complementary role played by the Nambu bracket. Since
the partition function of the superconformal Chern-Simons theory implies a
hidden super gauge group, we study the supersymmetric generalization of the
Nambu bracket. We explicitly construct the superunitary Nambu algebra.
