FOSSIL, or Formation of the Outer Solar System: An Icy Legacy, is an intensive survey program of the Subaru telescope using the HyperSuprimeCam. The goal of the program is to measure the populations and characterisics of the Jupiter Trojans and the various dynamical subpopulations of the small bodies in the Trans-Neptnuian region. The results of this survey program will provide important clues to our understanding of the formation and evolution of our Solar System.