  In this review article we study type IIB superstring compactifications in the
presence of space-time filling D-branes while preserving N=1 supersymmetry in
the effective four-dimensional theory. This amount of unbroken supersymmetry
and the requirement to fulfill the consistency conditions imposed by the
space-time filling D-branes lead to Calabi-Yau orientifold compactifications.
For a generic Calabi-Yau orientifold theory with space-time filling D3- or
D7-branes we derive the low-energy spectrum. In a second step we compute the
effective N=1 supergravity action which describes in the low-energy regime the
massless open and closed string modes of the underlying type IIB Calabi-Yau
orientifold string theory. These N=1 supergravity theories are analyzed and in
particular spontaneous supersymmetry breaking induced by non-trivial background
fluxes is studied. For D3-brane scenarios we compute soft-supersymmetry
breaking terms resulting from bulk background fluxes whereas for D7-brane
systems we investigate the structure of D- and F-terms originating from
worldvolume D7-brane background fluxes. Finally we relate the geometric
structure of D7-brane Calabi-Yau orientifold compactifications to N=1 special
geometry.
