The Connexions project at Rice University has created an open repository of educational materials and tools to promote sharing and exploration of knowledge as a dynamic continuum of interrelated concepts. Available free of charge to anyone under open-content and open-source licenses, Connexions offers high-quality, custom-tailored electronic course material, is adaptable to a wide range of learning styles, and encourages students to explore the links among concepts, courses, and disciplines. Connexions fosters worldwide, cross-institution communities of authors, instructors, and students, who collaborate on the creation of knowledge building blocks from which courses are constructed. The ideas and philosophy embodied by Connexions have the potential to change the very nature of teaching and learning, producing a dynamic, interconnected educational environment that is pedagogically sound, both time and cost efficient, and engaging.