Isaac Asimov's Foundation novels are a cornerstone of science fiction, but getting into a vast series about, among other things, mathematically predicting the rise and fall of entire civilizations isn't always easy. In 1973, however, the BBC adapted Foundation into a serial radio drama, capturing the original trilogy in eight hour-long episodes. These are available on the Internet Archive, which means that you can listen to them online or download them in all their slightly scratchy glory. Like some of the other radio drama we've highlighted, this adaptation has been online for some time, but it's still a fun and accessible way to discover a classic series. If you're unfamiliar with Foundation, economist Paul Krugman has also recently written about how its vision of society and science shaped his life.