Double examines the implications, practical and moral, of stealing someone else's identity. When Chap takes the seemingly perfect opportunity he's presented with, he thinks he's found the easy way out of a hard life. He doesn't realize at the outset, however, that in order to keep up the charade he would have to "live on a knife edge," always paranoid about someone discovering his deception. In this sense, a recurring theme in the book is false appearances: something or someone looking like one thing on the outside, but something completely different inside. The title of the novel, Double, even hints at this dichotomy.
Many elements of the book reflect this theme: Chap's role as Cassiel, Frank's outward appearance of success juxtaposed against his true nature, and Floyd's awkward appearance and good heart are only a few examples. While living Cassiel's life, Chap gradually realizes that it is a double all on its own; nothing is exactly as it seemed from the outside. The real Cassiel looked nothing like his public persona, and that conundrum is wrapped up in the overarching mystery of the novel: what happened to Cassiel Roadnight?
Interestingly, only the characters who are mostly independent fare well in this book. There seems to be an underlying message about parasitic living. Chap literally lives off someone else's life, and this is a major source of stress to him. Frank lives by draining money out of someone else's account illegally after robbing and murdering him, essentially a parasite in his very nature, and he has to resort to murder and constant deception in order to survive. He eventually winds up in prison anyway. Cassiel was just beginning to turn parasitic, blackmailing Frank out of his stolen money, when he was murdered.
The abruptness and irrationality of tragedy also emerges as an important element of the novel. When Chap's "Grandad" fell and broke both his hips, it happened "just like that. One, two, three, snap" (Ch. 17). Chap has a hard time believing that "something so good could be there one day and gone the next." He also muses on the little, almost meaningless roots of huge problems: "the phone call that causes a car crash, the delayed train that kicks off an affair, the whiskey shortage that turned me into a nobody" (Ch. 17).
This thriller seems written mostly to scintillate, but there are some deeper questions involved: is the grass really always greener on the other side? Is it ever acceptable to present a public version of yourself that is only a façade? What is the psychological toll of deception?
