Marine deltaic regions have been vitally important for development of the world's human civilization for at least the past 7,000 years due primarily to abundant natural resources and ease of transportation. In the past ~60 years, deltas such as the Mississippi River delta plain have added appeal due to abundant and easily exploitable energy and mineral deposits. This quest for oil and gas and sulfur was the impetus for the early research by Fisk, Frazier, Coleman and others to follow in Louisiana to decipher the Quaternary stratigraphy and structure and geologic development of the delta complex. The work of these researchers and the models developed for the Mississippi River delta have found application for other Holocene delta complexes around the world and increased understanding of the architecture and development of ancient deltas as well. In the past 20 years the scientific focus of interest in the delta has broadened with the recognition that very rapid erosion of the barrier islands(~10m/yr) and loss of valuable wetland ecosystems is occurring, but the rates, causes and processes are mostly unknown. Research by the USGS and Louisiana university scientists since 1985 has entailed interpreting hi-res seismic and vibracore data to better understand the geologic framework and processes of the delta-coastal system; detailed mapping and quantifying historic barrier erosion and wetland loss and linking the loses to processes; studying subsidence/sea-level rise, including man-made factors; modeling effects of climate change on the delta ecosystem; and locating and characterizing marine sand bodies suitable for barrier nourishment. Results of all these studies are finding application in the Federal/State CWPPRA restoration projects underway since 1990 and these studies combined with new research in the next decade are critical for successfully implementing the $14B Coast 2050 coastal restoration program.