  The theory of the usual, constrained p-branes is embedded into a larger
theory in which there is no constraints. In the latter theory the
Fock-Schwinger proper time formalism is extended from point-particles to
p-branes which can be considered as a points in an infinite dimensional space
M. The quantization appears to be straightforward and elegant. The conventional
p-brane states are particular stationary solutions to the functional
Schr\"odinger equation which describes the evolution of a membrane's state with
respect to the invariant evolution parameter $\tau$. It is also shown that
states of a lower dimensional p-brane can be considered as particular states of
a higher dimensional p-brane.
