We discuss duality between type IIA string theory, eleven-dimensional
supergravity, and heterotic string theory in four spacetime dimensions
with N = 1 supersymmetry. We find theories whose infrared limitis tri
vial at enhanced symmetry points as well as theories with N = 1 supers
ymmetry but the field content of N = 4 theories which flow to the N =
4 fixed line in the infrared.