We consider modules E over a C-algebra A which are equipped with a ma
p into A(+) that has the formal properties of a norm. We completely de
termine the structure of these modules. In particular, we show that if
A has no nonzero commutative ideals then every such E must be a Hilbe
rt module. The commutative case is much less rigid: If A = C-o(X) is c
ommutative then E is merely isomorphic to the module of continuous sec
tions of some bundle of Banach spaces over X. In general E will embed
in a direct sum of modules of the preceding two types.