An art form combining the skills of a DJ with the intimacy of a letter, a good mixtape was the ultimate audio valentine. Today, when the iPod and playlists reign supreme, the cassette has been rendered obsolete, and the art of crafting these sonic calling cards has been relegated to back-of-the-closet, thirty-something nostalgia. Now, thanks to Jason Bitner, we can relive our lost youth and lost loves. In "Cassette from My Ex," sixty noted writers...