A reflection on the evolution of physical media into metaphor, through the history of music curation.   Obsolescence makes the heart grow fonder, at least in the case of the mixtape. Not all technologies are so lucky. Some (say, wax cylinders) fade almost completely from cultural memory. A lucky few pass into metaphor: we still “hang up” our smartphones, “cut” film, and “patch” computer code. As digital streaming completes the obsolescence of physical media, what will become of the humble cassette? In The Last Mixtape, Seth Long offers a microhistory of music curation, anchored by the cassette, from which he explores the meanings of obsolescence, ownership, nostalgia, and the speed of cultural change. A moving meditation on our relationship with music, memory, and curation in the digital century, Long ultimately calls for a return to the media ecology represented by the mixtape: a world in which media is cheap and abundant but tactile and meaningfully engaged.