  We outline a general geometric structure that underlies the N=1
superpotentials of a certain class of flux and brane configurations in type II
string compactifications on Calabi-Yau threefolds. This ``holomorphic N=1
special geometry'' is in many respects comparable to, and in a sense an
extension of, the familiar special geometry in N=2 supersymmetric type II
string compactifications. It puts the computation of the instanton-corrected
superpotential W of the four-dimensional N=1 string effective action on a very
similar footing as the familiar computation of the N=2 prepotential F via
mirror symmetry. In this note we present some of the main ideas and results,
while more details as well as some explicit computations will appear in a
companion paper
