  We determine the rate region of the quadratic Gaussian two-encoder
source-coding problem. This rate region is achieved by a simple architecture
that separates the analog and digital aspects of the compression. Furthermore,
this architecture requires higher rates to send a Gaussian source than it does
to send any other source with the same covariance. Our techniques can also be
used to determine the sum rate of some generalizations of this classical
problem. Our approach involves coupling the problem to a quadratic Gaussian
``CEO problem.''
