"You can see the entire problem set online, thanks to the U.S. Library of Congress, which recently digitized and posted course materials from this and one other

"You can see the entire problem set online, thanks to the U.S. Library of Congress, which recently digitized and posted course materials from this and one other class Sagan taught, at Cornell University. [...] Sagan may have been best known for his popular science books and TV show, Cosmos, but he also taught college classes for three decades."