Massachusetts Institute of Technology (MIT) is a world-class educational Institution. It is to be said the best technical institution in United States. As I am from Mexico, I think of it as the TEC de Monterrey of United States.
Recently, the Institute has opened up the knowledge across the world by offering the possibility of downloading entire courses (lecture notes, exams and videos) for free.
The concept is called Open Course Ware and it allows self-learning and benchmark teaching.
You can download courses and resources from departments such as Architecture and Planning, Engineering, Health Sciences and Technology, Humanities, Arts, Social Sciences, Management and much more...
I have already downloaded a course on Writing... It is a very good source for knowledge but also as reference for books and publications.
Their slogan: "Unlocking Knowledge, Empowering Minds"
Give it a try