In this paper, we prove a theorem on boundary perturbation of nonautonomous
Cauchy problems and then apply this result to show the existence and uniqu
eness of classical solutions of the nonautonomous, Banach space valued func
tional differential equation
{x'(t) = A(t)x(t) + K(t)x(t), 0 less than or equal to t less than or equal
to T, {x(tau) = phi(tau - s), s - r less than or equal to tau less than or
equal to s. (C) 1999 Academic Press.