»The Way (or Means, or Rules) of Cooking«: the oldest English-language cookbook. (»Forme« ought to be rather self-explanatory; »cury« here is the same word as »cure«, as in e.g. cured meat; at the time, it basically meant cooking.) Written circa 1390 and claiming to be the work of »The Chief Master-Cooks of King Richard II«, it contains, by the reckoning of the printed edition of 1780, 196 recipes; it will teach you how to prepare valuable dishes such as flaumpens, roo broth and chebolace. Fortunately, its copyright is now expired, and it can be found in numerous editions both in print and online, so that all men may partake of its ancient wisdoms. And a good thing, too; you would look like a damn idiot if you didn't know how to cook roo broth at your age.
In fact, the book is quite interesting, not least for its heavy use of spices and sugar, which is probably a product of its origins in the royal kitchens; these were expensive ingredients, and are no doubt commonly included just to show off. Using it in practice is likely to be difficult for anyone who isn't already an accomplished cook, however, because like other medieval and renaissance cookbooks it doesn't specify amounts, temperatures or times at all — this doesn't seem to have occurred to anybody as a good idea until the 18th century. Consequently, if you were to try one of the recipes but couldn't intuit all these things you'd probably find yourself in trouble pretty quickly.