Asymptotic morphisms on C* algebras and their compositions were introduced
by Connes and Higson. This paper considers definitions of asymptotic morphi
sms oil separable metrisable algebras, and a compatibility condition is giv
en which allows the composition of such morphisms. A class of algebras is d
efined, with the property that every bounded set has compact closure, where
the compatibility conditions are automatically satisfied. Three examples a
re given in detail, the first involving a non-normable algebra due to Ellio
tt, Natsume and Nest. The second is integration with respect to a certain q
uasi-commutative spectral measure on the algebra of paths on a C* algebra,
and the third the equivalence between the suspensions of the mapping cone a
nd the ideal for a short exact sequence of C* algebras. (C) 2000 Academic P
ress.