The workshop brought together experts in astronomy and particle physics to make the science case for a satellite mission to measure the polarization of the cosmic microwave background (CMB). Detailed maps of the CMB polarization will potentially reveal clues about the origin of the universe. An early epoch of inflation typically produces a spectrum of gravitational waves and these leave a distinctive imprint on the CMB polarization field. The workshop addressed all theoretical aspects of this science: which inflationary models predict an amplitude that will be detected and which do not? What do alternatives to inflation predict? Apart from the gravitational wave signal, what other science can be gleaned from these measurements? High resolution maps should have traces of gravitational lensing which in turn is affected by dark energy and massive neutrinos. How well will a satellite mission be able to measure these effects? CMB polarization also speaks to the end of the Dark Ages; the constraints on reionzation are discussed in the context of all other probes. Finally, several articles - based on many talks and follow-up work - probe the science of and removal of Galactic foregrounds.