  A correspondence between type IIB string theory with N D7-branes on R^{1,3} x
C^1/Z_2 x T^2/Z_2 x T^2/Z_2 and pure N=1 SU(N) gauge theory in four dimensions
is proposed and argued. First the supergravity background of unwrapped and flat
D7-branes with running axion and dilaton on R^{1,7} x C^1/Z_2 is studied
together with the corresponding N=1 SU(N) gauge theory in eight dimensions. The
D7-branes are then wrapped over a 4-cycle on T^2/Z_2 x T^2/Z_2 which turns on
all F_1, F_3, H_3, and F_5 fluxes of type IIB theory and induces torsion. The
supergravity solutions are explicitly constructed with exact analytic
expressions for all components of the metric and the fluxes. The background
geometry of the four-dimensional gauge theory is compact and conformally
Calabi-Yau. The internal space normal to the wrapped D7-branes at the infrared
boundary is S^1 whose radius is set by the nonperturbative scale of the gauge
theory and spacetime is R^{1,3} at the ultraviolet boundary. The gauge coupling
of the four-dimensional gauge theory is related to the gauge coupling of the
eight-dimensional gauge theory and the volume of the 4-cycle. The gravity
theory reproduces the renormalization group flow and the pattern of chiral
symmetry breaking of the gauge theory and leads to confinement. The curvature
is small and nearly constant and the supergravity flow is smooth in the
infrared region where the gauge theory is strongly coupled and a dual gravity
description is useful. String loop corrections are small for large N. The scale
of string tension in four dimensions is of the same order as the scale of
Kaluza-Klein masses.
