Like many of the author's later triumphs, this one revolves around a question of identity. The late Sebastian Knight, we discover, was a transplanted Russian novelist whose taste for linguistic trickery bears a certain resemblance to Nabokov's. Now his half-brother is attempting to reconstruct the existence of this elusive figure. As he readily admits, the raw material isn't exactly the stuff of melodrama: "Sebastian's life, though far from being dull, lacked the terrific vigour of his literary style." But even the most mundane facts prove difficult for the narrator to nail down. He does, on the other hand, describe Sebastian's creative processes in exquisite and accurate detail:

His struggle with words was usually painful and this for two reasons. One was the common one with writers of his type: the bridging of the abyss lying between expression and thought; the maddening feeling that the right words, the only words are awaiting you on the opposite bank in the misty distance, and the shudderings of the still unclothed thought clamouring for them on this side of the abyss.