Thomas Keller, chef/proprieter of Napa Valley's French Laundry, is passionate about bistro cooking. He believes fervently that the real art of cooking lies in elevating to excellence the simplest ingredients; that bistro cooking embodies at once a culinary ethos of generosity, economy, and simplicity; that the techniques at its foundation are profound, and the recipes at its heart have a powerful ability to nourish and please. So enamored is he of this older, more casual type of cooking that he opened the restaurant Bouchon, right next door to the French Laundry, so he could satisfy a craving for a perfectly made quiche, or a gratineacute;ed onion soup, or a simple but irresistible roasted chicken. Now Bouchon , the cookbook, embodies this cuisine in all its sublime simplicity. But let's begin at the real beginning. For Keller, great cooking is all about the virtue of process and attention to detail. Even in the humblest dish, the extra thought is evident, which is why this food tastes so amazing: The onions for the onion soup are caramelized for five hours; lamb cheeks are used for the navarin; basic but essential refinements every step of the way make for the cleanest flavors, the brightest vegetables, the perfect balance-whether of fat to acid for a vinaigrette, of egg to liquid for a custard, of salt to meat for a duck confit. Because versatility as a cook is achieved through learning foundations, Keller and Bouchon executive chef Jeff Cerciello illuminate all the key points of technique along the way: how a two-inch ring makes for a perfect quiche; how to recognize the right hazelnut brown for a brown butter sauce; how far to caramelize sugar for different uses. But learning and refinement aside-oh those recipes! Steamed mussels with saffron, bourride, trout grenobloise with its parsley, lemon, and croutons; steak frites, beef bourguignon, chicken in the pot-all exquisitely crafted. And those immortal desserts: the tarte Tatin, the choco