Bauer first saw the Codex Cardona in 1985 in the Crocker Nuclear Laboratory at the University of California, Davis, where scholars from Stanford and the University of California were attempting to establish its authenticity. Allowed to gently lift a few pages of this ancient treasure, Bauer was hooked. By 1986, the Codex had again disappeared from public view. Bauer’s curiosity about the Codex and its whereabouts led him down many forking paths—from California to Seville and Mexico City, to the Firestone Library in Princeton, to the Getty Museum in Los Angeles and Christie’s in New York—and it brought him in contact with an international cast of curators, agents, charlatans, and erudite book dealers. The Search for the Codex Cardona is a mystery that touches on issues of cultural patrimony, the workings of the rare books and manuscripts trade, the uncertainty of archives and evidence, and the ephemerality of the past and its remains.