Pale Fire is a Jack-in-the-box, a Faberge gem, a clockwork toy, a chess problem, an infernal machine, a trap to catch reviewers, a cat-and-mouse game, a do-it-yourself novel. It consists of a 999-line poem of four cantos in heroic couplets together with an editor's preface, notes, index, and proof-corrections. When the separate parts are assembled, according to the manufacturer's directions, and fitted together with the help of clues and cross-references, which must be hunted down as in a paper-chase, a novel on several levels is revealed, and these "levels" are not the customary "levels of meaning" of modernist criticism but planes in a fictive space, rather like those houses of memory in medieval mnemonic science, where words, facts, and numbers were stored till wanted in various rooms and attics, or like the Houses of astrology into which the heavens are divided.

By Mary McCarthy
https://newrepublic.com/article/63440/bolt-the-blue