Bob Geroch at Chicago has recently installed a new website (or at least new to me, thanks to David Malament for the pointer!) containing links to many of his lecture notes that he has written over the years. Here is the URL:
Some of the files are rather large, as they are scanned from physical originals. But as David Malament writes, “[t]here is pure gold here for those interested in the mathematical foundations of physics.” I couldn’t agree more!