Rationale: For centuries, theories of planet formation were guided exclusively by our solar system. However, the discovery of planets orbiting other stars (exoplanets) in the past two decades has demonstrated that nature often produces planetary systems quite different from our own, neither anticipated by nor well explained by the current theories of solar system formation and dynamics. The diversity of planetary system architectures (the masses and orbital arrangements of planets) has confronted astronomers with many new challenges and reinvigorated the fields of planet formation and orbital dynamics. Among these challenges are planetary systems with multiple planets in close-in orbits, highly eccentric orbits, and planets in binary star systems. In this one week program, scientists from the fields of planetary science, celestial mechanics, astronomy and astrophysics will meet to discuss new developments in the field of extrasolar multi-planet systems. The goal of our workshop is to provide an environment where these scientists can present new ideas, discuss their implications for identifying the most important problems in the field and chart the field’s future direction.