Environmental challenges continue to multiply as the global population expands toward 10 billion people by 2050 and as demands for clean water, food, and energy rise, all in the context of global climate change. This study will bring together experts in a wide range of fields who, with input from the scientific community and the broader public, will identify the biggest challenges that environmental engineers and the aligned sciences will need to address over the next several decades. The study also will describe how the field—and colleges and universities—might evolve to better address those challenges.