Readers of physical books leave traces: marginalia, slips of paper, fingerprints, highlighting, inscriptions. All books have histories, and libraries are not just collections of books and databases, but a medium of long-distance communication with other writers and readers."Letter to a Future Lover" is a collection several dozen brief pieces written by Ander Monson in response to library ephemera-with "library" defined broadly, ranging from university institutions to friends' shelves, from a seed library to a KGB prison library-and addressed to readers past, present, and future.