Overview: COSMOS-Web (PID: 1727) is a 255 hour wide-field Cycle 1 JWST treasury program that maps a contiguous 0.6 deg2 area with deep NIRCam imaging in 4 filters (F115W, F150W, F277W, and F444W) and a non-contiguous 0.2 deg2 area with MIRI in parallel. COSMOS-Web builds on the rich heritage of multiwavelength observations and data products available in the COSMOS field and will contain about a million galaxies across cosmic time. The survey will be completed by the end of 2023. The three primary science drivers of COSMOS-Web are to (1) Revolutionize our understanding of reionization's spatial distribution, environments, and drivers at early stages by detecting thousands of galaxies in the epoch of reionization (6<z<11) on scales large enough to mitigate cosmic variance; (2) Enable the identification and characterization of massive galaxies in the first two billion years, including the rarest quiescent galaxies at z > 4, and allow us to constrain the formation and evolution of early massive galaxies; and (3) Directly measure the evolution of the stellar mass to halo mass relation (SMHR) out to z ~ 2.5 and its variance with galaxies' star formation histories and morphologies.