• Un jour, un collègue invite Raymond Smullyan à dîner en précisant : "Mon fils sera ravi de faire ta connaissance car il est passionné par tes livres d'énigmes!". Smullyan : "D'accord, mais je t'interdis de lui dire que je suis mathématicien!"En apprenti sorcier des mathématiques, Raymond Smullyan avance masqué. Avec Le Livre qui rend fou, un recueil d'énigmes stimulantes et ludiques, il guide le lecteur dans le monde étrange de la logique, sans jamais se départir de son humour et de sa fantaisie. Attention, en vous plongeant dans ce livre, vous risquez d'y perdre la tête!

  • Un homme regarde un portrait. Quelqu'un lui demande: "Qui regardez-vous?" Il répond: "Je n'ai point de frère ni de soeur mais le père de cet homme est le fils de mon père" De qui regarde-t-il le portrait?
    Ce problème  est l'un des nombreux casse-tête concoctés pour vous par le très ingénieux Raymond Smullyan :  de quoi booster vos neurones!

  • Dans le désert, un chameau se dirige vers l'Est. Un autre vers l'Ouest. Comment fontils pour se regarder ?
    Voici, résumée, l'une des plus simples parmi les 200 devinettes que la malicieuse princesse soumet au roi son mari pour le tenir en haleine. Mathématicienne ou logicienne, la Shéhérazade de Smullyan ajourne ainsi habilement, nuit après nuit, l'échéance de son exécution.
    D'austère, la logique se change en une plaisante discipline et le paradoxe d'Epiménide, le théorème de Gödel, le paradoxe de Russell ou encore le célèbre dilemme du prisonnier nous apparaissent soudain tout à fait accessibles.
    Alliance savoureuse du drôle et du sérieux, du légendaire et du réel, ce livre enchantera les amoureux des mathématiques, les esprits férus de problèmes logiques. Les solutions figurent en fin d'ouvrage !

  • More than two hundred new and challenging logic puzzles--the simplest brainteaser to the most complex paradoxes in contemporary mathematical thinking--from our topmost puzzlemaster (the most entertaining logician who ever lived, Martin Gardner has called him).
    Our guide to the puzzles is the Sorcerer, who resides on the Island of Knights and Knaves, where knights always tell the truth and knaves always lie, and he introduces us to the amazing magic--logic--that enables to discover which inhabitants are which. Then, in a picaresque adventure in logic, he takes us to the planet Og, to the Island of Partial Silence, and to a land where metallic robots wearing strings of capital letters are noisily duplicating and dismantling themselves and others. The readers job is to figure out how it all works.
    Finally, we accompany the Sorcerer on an alluring tour of Infinity which includes George Cantors amazing mathematical insights. The tour (and the book) ends with Satan devising a diabolical puzzle for one of Cantors prize students--who outwits him!
    In sum: a devilish magicians cornucopia of puzzles--a delight for every age and level of ability.

  • In this entertaining and challenging new collection of logic puzzles, Raymond Smullyan--author of What Is the Name of This Book? And The Lady or the Tiger?--continues to delight and astonish us with his gift for making available, in the thoroughly pleasurable form of puzzles, some of the most important mathematical thinking of our time.
    In the first part of the book, he transports us once again to that wonderful realm where knights, knaves, twin sisters, quadruplet brothers, gods, demons, and mortals either always tell the truth or always lie, and where truth-seekers are set a variety of fascinating problems. The section culminates in an enchanting and profound metapuzzle (a puzzle about a puzzle), in which Inspector Craig of Scotland Yard gets involved in a search of the Fountain of Youth on the Island of Knights and Knaves.
    In the second and larger section, we accompany the Inspector on a summer-long adventure into the field of combinatory logic (a branch of logic that plays an important role in computer science and artificial intelligence). His adventure, which includes enchanted forests, talking birds, bird sociologists, and a classic quest, provides for us along the way the pleasure of solving puzzles of increasing complexity until we reach the Master Forest and--thanks to Gödels famous theorem--the final revelation.
    To Mock a Mockingbird will delight all puzzle lovers--the curious neophytes as well as the serious students of logic, mathematics, or computer science.

  • Forever Undecided is the most challenging yet of Raymond Smullyans puzzle collections. It is, at the same time, an introduction--ingenious, instructive, entertaining--to Gödels famous theorems.
    With all the wit and charm that have delighted readers of his previous books, Smullyan transports us once again to that magical island where knights always tell the truth and knaves always lie. Here we meet a new and amazing array of characters, visitors to the island, seeking to determine the natives identities. Among them: the census-taker McGregor; a philosophical-logician in search of his flighty bird-wife, Oona; and a regiment of Reasoners (timid ones, normal ones, conceited, modest, and peculiar ones) armed with the rules of propositional logic (if X is true, then so is Y). By following the Reasoners through brain-tingling exercises and adventures--including journeys into the other possible worlds of Kripke semantics--even the most illogical of us come to understand Gödels two great theorems on incompleteness and undecidability, some of their philosophical and mathematical implications, and why we, like Gödel himself, must remain Forever Undecided!

  • In his new book, Raymond Smullyan, grand vizier of the logic puzzle, joins Scheherazade, a charming young woman of fantastic logical ingenuity, to give us 1001 hours of brain-teasing fun.
    Scheherazade, we find, has gotten back into hot water with the king, and is once more in danger of losing her head at down. But, thinking quickly, she tempts the king to stay her execution by posing him the most delightfully devious mathematical and logic puzzle ever invented. They keep him guessing for many more nights until the fatal hour has passed, and she keeps her head.
    The Riddle of Scheherazade includes several wonderful old chestnuts and many fiendishly original puzzles, 225 in all. There are logic tricks and number games, metapuzzles (puzzles about puzzles), liar/truth-teller exercises, Gödelian brian twisters, baffling paradoxes, and an excursion, under Scheherazades expert guidance, into an amusing new field invented by Smullyan, called coercive logic, in which the answer to a problem can actually change the fate of the puzzler!
    An absolute must for all puzzle fans--from the middle-school whiz to the sophisticated mathematician or computer scientist.

  • Kurt Godel, the greatest logician of our time, startled the world of mathematics in 1931 with his Theorem of Undecidability, which showed that some statements in mathematics are inherently undecidable. His work on the completeness of logic, the incompleteness of number theory, and the consistency of the axiom of choice and the continuum theory brought him further worldwide fame. In this introductory volume, Raymond Smullyan, himself a well-known logician, guides the reader through the fascinating world of Godel's incompleteness theorems. The level of presentation is suitable for anyone with a basic acquaintance with mathematical logic. As a clear, concise introduction to a difficult but essential subject, the book will appeal to mathematicians, philosophers, and computer scientists.