  The massive IIA string theory whose low energy limit is the massive
supergravity theory constructed by Romans is obtained from M-theory
compactified on a 2-torus bundle over a circle in a limit in which the volume
of the bundle shrinks to zero. The massive string theories in 9-dimensions
given by Scherk-Schwarz reduction of IIB string theory are interpreted as
F-theory compactified on 2-torus bundles over a circle. The M-theory solution
that gives rise to the D8-brane of the massive IIA theory is identified.
Generalisations of Scherk-Schwarz reduction are discussed.
