One of California's most remarkable wetlands, Suisun Marsh is the largest tidal marsh on the West Coast and a major feature of the San Francisco Estuary. This productive and unique habitat supports endemic species, is a nursery for native fishes, and is a vital link for migratory waterfowl. The 6,000—year—old marsh has been affected by human activity, and humans will continue to have significant impacts on the marsh as the sea level rises and cultural values shift in the century ahead. This study includes in—depth information about the ecological and human history of Suisun Marsh, its abiotic and biotic characteristics, agents of ecological change, and alternative futures facing this ecosystem.