The name of this collection derives from medieval celebrating "Day of the Fools". During that celebrating all conventionalities were postponed, and the buffoon-king, which had his own court, ruled the Fool Kingdom. The tradition to keep the fools at royal courts and in houses of noble families was proceeded from antiquity up to XVII century. The fools were frequently the feeble-minded people, but they were considered (often not without reason) having exceptional relations with the mystical life. Such "God's fools", though produced laughter, were held in high respect and care of the community. In literary tradition (for example, in Shakespeare's plays) the fool was frequently a royal companion, close confidant and privileged critic. A Fool personified freedom, because he could speak whatever he likes. His statements, looking like silly, could infuriate the inflated, but stupid peoples. Other words, wisdom and foolishness, their unity and contradiction are the theme of the given collection.