We continue our study or the general theory of possibly nonselfadjoint alge
bras of operators on a Hilbert space, and modules. over such algebras, deve
loping a little more technology to connect "nonselfadjoint operator algebra
" with the C*-algebraic framework. More particularly, we make use of the un
iversal, or maximal, C*-algebra generated by an operator algebra, and C*-di
lations. This technology is quite general, however it was developed to solv
e some problems arising. in the theory of Morita equivalence of operator al
gebras, and as a result most of the applications given here (and in a compa
nion paper) are to that subject. Other applications given here are to exten
sion problems for module maps. and characterizations of C*-algebras. (C) 19
99 Academic Press.