Scattering amplitudes have played a central role in quantum field theory since its inception. Recent years have seen a remarkable advance in our understanding and in our ability to compute scattering amplitudes, both for theoretical and phenomenological purposes. Scattering amplitudes in gauge and gravity amplitudes have a remarkably rich yet simple structure, allowing us to develop ever more powerful means of understanding their behavior. Among the important recent developments is the maturation of on-shell methods as a standard tool for exploring scattering amplitudes. With the imminent arrival of the Large Hadron Collider (LHC) at CERN, it is clear that in the coming years scattering amplitudes and cross-sections will take on an even more prominent role in particle physics.

In quantum chromodynamics (QCD), tremendous progress has been made on obtaining new precision predictions of direct relevance to experiments at the LHC. In more formal areas, an exciting new venue for studying Maldacena's AdS/CFT duality between string theory and field theory has been opened, linking scattering amplitudes in maximally supersymmetric Yang-Mills theory to string theory in anti-de-Sitter space. Similarly, our improved understanding of scattering amplitudes has directly challenged basic premises on the ultraviolet behavior of quantum gravity. It may even be that N = 8 supergravity, once thought to be an enormously complicated theory, is in fact the simplest of all four-dimensional quantum field theories. Even more remarkable are various relations between gravity and gauge theory scattering amplitudes, suggesting a unification between these theories of the sort inherent to string theory.

The key goal of this workshop is not only to consolidate the new advances, but to cross-fertilize different sub-disciplines, charting future advances. Our plan is to bring together people working in more formal areas with those working on more phenomenologically oriented subfields. We believe that not only are we at the cusp of revolutionizing the way we view scattering amplitudes, but the new ideas will have an important impact in other areas as well. To facilitate this we plan to invite theorists with expertise outside of scattering amplitudes, especially during a two-week tutorial period. We also plan to periodically invite experimenters to help focus the discussions to issues of direct interest to the experimental community. We plan to be flexible, altering the relative emphasis of the program, depending on new theoretical developments and especially on any new findings at the LHC.