  The positive potential energy required for inflation spontaneously breaks
supersymmetry and in general gives any would-be inflaton an effective mass of
order the inflationary Hubble parameter thus ruling it out as an inflaton. In
this paper I give simple conditions on the superpotential that eliminate some
potential sources for this mass, and derive a form for the Kahler potential
that eliminates the rest. This reduces the problem of constructing a model of
inflation in supergravity to that of constructing one in global supersymmetry
with the extra conditions $W=W_\varphi=\psi=0$ during inflation (where $W$ is
the superpotential, the inflaton $\in\varphi$, and $W_\psi\neq0$). I then point
out that Kahler potentials of the required form often occur in superstrings and
that the target space duality symmetries of superstrings often contain
R-parities which would make $W=W_\varphi=0$ automatic for $\psi=0$.
