Research on remediation of subsurface contamination is helping to solve important environmental problems associated with hazardous and radioactive contaminants in soil and groundwater. In the United States, significant research in this area has been sponsored by the U.S. Department of Energy (DOE) Environmental Management Science Program (EMSP), which seeks to advance scientific knowledge and technological solutions to reduce environmental cleanup costs, schedules, and risks. This symposium series book presents leading-edge research being conducted through the EMSP in the subsurface contamination area. The chapters, addressing problems prevalent at both federal and industrial sites, are organized into three sections focusing on (1) remedial science and technology for subsurface contamination, (2) characterization, fate, and transport of subsurface contamination, and (3) environmental sensing and monitoring. The selected contributors invited from the overall DOE EMSP portfolio of 361 projects represent work being done across the country in universities and National Laboratories.