The Fifth Annual Educause Current Issues Survey ranked "security and identity management" near the top of the list of critical IT challenges on campus today. Recognition of the crucial importance of securing networked resources led Internet2 to establish its Middleware Initiative (I2MI) in 1999. While Internet2 was founded to develop and deploy advanced network technologies and applications, it was clear from the start that high-speed networks would simply provide a quicker path to abuse unless improved methods of managing and controlling access to resources were developed and deployed along with those networks. I2MI has brought together campus middleware architects to work on fundamental issues in authentication, authorization, and directory services to make secure inter-institutional services possible and practical. The most innovative I2MI effort to date is the Shibboleth Project. Its primary product, the Shibboleth System (often called just Shibboleth), provides an effective solution for secure multi-organizational access to Web resources. In this article, the authors describe how it works, its key features, and how it is designed to meet the needs of the higher education and research communities and their partners. (Contains 2 endnotes.)