If Dan Brown’s latest is The Lost Symbol, you might say Nabokov’s Laura is The Last Symbols: his final written words, the draft he wanted burned if he died before completing it. The one that had been secreted away in a strongbox in a Swiss bank vault for decades. The one that existed in the form of 138 index cards, covered with his pencil-written prose. The one—and this is what made it so seductive, an object of worldwide fascination among littérateurs—that might contain a clue or clues, a code, for all we knew, that would offer new perspective on the often cryptic prose of past Nabokov masterpieces.