Non-indigenous species (NIS) are common in the United States landscape. While some are beneficial, others are harmful and can cause significant economic, environmental, and health damage. This study, requested by the U.S. House Merchant Marine and Fisheries Committee, examined State and Federal policies related to these harmful NIS. The report is presented in 10 chapters. Chapter 1 identifies the issues and options related to the topic and a summary of the findings from the individual chapters that follow. Chapters 2 "The Consequences of NIS" and 3 "The Changing Numbers, Causes, and Rates of Introductions" examine basic aspects of NIS, their effects, how many there are, and how they get here. Technologies to deal with harmful NIS, including decision-making methods and techniques for preventing and managing problem species, are covered in chapters 4 "The Application of Decisionmaking Methods" and 5 "Technologies for Preventing and Managing Problems." Chapters 6, "A Primer on Federal Policy," 7 "State and Local Approaches from a National Perspective," and 8 "Two Case Studies: Non-Indigenous Species in Hawaii and Florida" assess what various institutions at the Federal, State, and local levels do, or fail to do, about NIS. Chapters 9 and 10 place NIS in a broader context by examining their relationships to genetically engineered organisms, to international law to other prominent environmental issues, and to choices regarding the future of the nation's biological resources. Appendixes include: lists of boxes, figures, and tables in the document; list of authors, workshop participants, reviewers, and survey respondents for the study; and list of references by chapter. Additional sections contain an index to common and scientific names of species, and a general index. (MDH)