In its original form, the Cookbook offered no guarantee of satiety. It contained, as doctrine required, every possible recipe; it followed that most were nonsense, many were poisonous, and a distressing number contained only onions.

Since the great purges of 823 and 1632 -- and those unspeakable lesser purges, initiated by weak men to settle petty debts and suppress certain compromising entries concerning nutmeg -- the Library has become somewhat easier to navigate. What remains is still vast, treacherous, and badly indexed, but the novice now has a reasonable chance of finding dinner before despair.

The greatest opportunity for success lies at the Giant Wheels of Chance in the centre of the Library. Though condemned by orthodox cataloguers as vulgar machinery, they are beloved by the hungry. Their ritual is simple, and therefore suspect:

Swipe a word right, or double-tap it, to replace an ingredient or method. Swipe left to banish it. Tap to pin anything worth preserving. Use + to add another element. The timid will note that this may exceed the holy seven; the bold will assert that fine dining often requires heresy. Pull down to re-roll everything that has not yet been pinned.

Continue until the dish begins to sound edible. This is not a science, though several ruined schools of librarians have insisted otherwise.

Browsing, building, and bookmarking dishes is completely free. Spin the wheels as often as you like; no account is required, and no oath need be sworn.

Have a code? Choose "write the recipe" on any dish. You will be asked once, and the code will be remembered on your device, unless your device is unusually devout.

The Cookbook is a place for the hungry. At its construction, the Library was designed to contain every possible recipe composed of seven ingredients selected from a canon of one thousand. This was its first heresy and its first consolation: that every supper, however exquisite or abominable, had already been written.

Centuries have passed since the death, disappearance, or apotheosis of the Man of the Book. The librarians, reduced now to sects, committees, and clans (guardians of hereditary grudges), still cling to the remnants of his filing system: a primitive artificial intelligence whose responses were once said to lead the faithful to delicacies of almost intolerable beauty. In the old catalogues it is named CLAUDE; some gloss this as Culinary Lexical Automaton for Universal Degustation and Exegesis, though the etymology is plainly spurious.

The rites by which the librarians consult it are superstitious, persistent, and not wholly ineffective. Generations of anxious query, correction, invocation, and complaint have worn literal furrows in the fabric of the Library. Aisles have buckled into shortcuts. Cupboards of false saffron have collapsed into cellars of edible onions. Whole galleries of rancid metaphysics have been rendered impassable, which even the orthodox concede is an improvement.

Nor has decay been the Library's only editor. The Purifiers, with their destructive rigour, have burned the monstrous volumes: recipes for soups of ash and mercury, cakes requiring the absence of flour, salads whose seventh ingredient is the cook. Their work is condemned by the moderate schools, but secretly valued by beginners. What remains, though diminished and still immeasurable, is more hospitable to appetite.

Initial navigation is nevertheless difficult. The novice cook must learn to distinguish a true recipe from a commentary, a commentary from a curse, and a curse from an overambitious marinade. Yet with patience, hunger, and the occasional ambiguous assistance of the resident intelligence -- which answers sometimes as Clod, and at others as the Cloud -- one may still discover, between two blasphemies and a misfiled gremolata, a dish both tasty and sufficient.

Those souls who cannot be satisfied merely by eating may consult the Great Graph: a map of the Cookbook so fiendishly complex that prolonged study risks dizziness, vanity, and the conviction that parsley is destiny.

The Graph reveals, or claims to reveal, the secret commerce between the Wheels of Chance, the surviving shelves, and the obscure appetites of CLOD. It shows how ingredients drift together, how methods cling to them, and how certain combinations -- once thought accidental -- recur with the persistence of bad theology.

No novice is required to understand the Graph. Indeed, most competent dinners are prepared in blessed ignorance of it. But for those who must know why the wheels favour chickpeas, why tarragon appears in times of civic decline, or by what logic CLOD mistakes soup for prophecy, the Graph offers dangerous inspiration.