MIT OpenCourseWare shares the course materials from classes taught on the MIT campus. In most cases, this takes the form of course documents such as syllabi, lecture notes, assignments and exams. Occasionally, however, we come across textbooks (and textbook-like course notes) that we can share openly.

UPDATE: As of May 20, 2014, please visit the new OCW Online Textbooks page for the latest index of over 45 textbooks.