A co-author of the blockbuster Wittgenstein's Poker is back with another book about the big personalities and bigger ideas of 20th century philosophy. In Would You Kill the Fat Man? (Princeton), podcasting philosopher David Edmonds weaves his narrative around an ethical hypothetical. An out-of-control trolley is headed straight for five people tied to a track. You have the power to divert the train onto a spur, thus killing only one person instead. What do you do? What should you do?

The book's title comes from a popular variation of the thought experiment, which involves pushing a fat man into the path of the trolley-an approach many find less morally palatable than the spur, for wildly complicated reasons.

Edmonds enjoyably traces the ever-expanding sub-genre of trolleyology through debates about language, abortion, cannibals, war, and a complicated love quadrangle involving the novelist Iris Murdoch and the philosopher Philippa Foot, offering insights on ethics, politics, and sex along the way. –Katherine Mangu-Ward