The lectures were later distributed for many years as samizdaţ by the Indiana University Linguistics Club, and finally published as a book in the 1990s. Every linguist is or should be familiar with them, but practically nobody else has ever heard of them.
Therefore, as a public educational service, I have scanned my old IULC copy and put them up on the Web, so that I and other teachers can link to them. The quality of reproduction is lousy, but -- in my estimation, and that of many others -- they're the best linguistic writing of the 20th century. They're worth it.
There are six lectures, available either as a single (3 MB) PDF:
or as individual PDFs, around 500 KB each: