String theory remains the best motivated and most encompassing approach to extending the Standard Model and answering questions the Standard Model does not address. The phenomenological aspects of string theories have received renewed attention in recent years. String theory incorporates mechanisms to stabilize the hierarchy, and generate electroweak symmetry breaking; it contains possible explanations of gauge coupling unification, light neutrinos, inflation and baryogenesis, as well as the dark matter and dark energy. String models can address flavor issues including the number of families, rare or forbidden decays, the values of quark and lepton masses (including neutrino masses), and CP violation. They have the potential to predict properties of superpartners that might be found at the Tevatron or LHC and provide new experimental tests and probes of the theory.

There has been continuing progress in improving understanding of many of the issues and problems in these areas. Studies of string vacua, and approaches based on flux compactifications, are making contact between theory and phenomenology in new and stimulating ways. In addition many experimental facilities that have been under construction, from the Tevatron and b-factories to dark matter and EDM experiments, and WMAP and PLANCK, have begun or will soon begin to take data that will test ideas. The LHC, which will turn on in 2007, will open an entirely new range of energy, and should answer the question of the origin of electroweak symmetry breaking, testing ideas such as supersymmetry and large or warped extra dimensions As the date that LHC turns on approaches, many theorists are showing new interest in how to relate possible LHC data to string theory.

This program will be broadly based and aim to take advantage of all recent developments. We will bring together both string theorists whose work has kept phenomenology in mind, and phenomenological theorists whose work has kept string theory in mind. And we also hope to attract mathematical string theorists whose work on compactifications can be very relevant to problems of string phenomenology, and cosmologists with an interest in very ear