Aquatic invasive species-harmful, nonnative plants, animals, and microorganisms living in aquatic habitats-damage ecosystems or threaten commercial, agricultural, and recreational activities. The Nonindigenous Aquatic Nuisance Prevention and Control Act of 1990 created the Task Force and required it to develop an aquatic nuisance species program. The Water Resources Reform and Development Act of 2014 includes a provision that the United States Government Accountability Office (GAO) assess federal costs of, and spending on, aquatic invasive species. This book examines how much Task Force member agencies expended addressing aquatic invasive species for fiscal years 2012-2014; activities conducted by Task Force member agencies and challenges in addressing aquatic invasive species; and the extent to which the Task Force has measured progress in achieving the goals of its 2013-2017 strategic plan.