The Domain Name System (DNS) enables user-friendly alphanumeric names—domain names—to be assigned to Internet sites. Many of these names have gained economic, social, and political value, leading to conflicts over their ownership, especially names containing trademarked terms. Congress, in P.L. 105-305, directed the Department of Commerce to request the NRC to perform a study of these issues. When the study was initiated, steps were already underway to address the resolution of domain name conflicts, but the continued rapid expansion of the use of the Internet had raised a number of additional policy and technical issues. Furthermore, it became clear that the introduction of search engines and other tools for Internet navigation was affecting the DNS. Consequently, the study was expanded to include policy and technical issues related to the DNS in the context of Internet navigation. This report presents the NRC’s assessment of the current state and future prospects of the DNS and Internet navigation, and its conclusions and recommendations concerning key technical and policy issues.