In his new collaborative cookbook, Under Pressure: Cooking Sous Vide (Artisan, $75), Keller introduces to the American chef the fascinating technique of "the twenty-first-century bain-marie", as Harold McGee puts it. While manning the stove at New York's Rakel in the 1980s, Keller vacuum-packed foie gras to eliminate oxidation and extend the delicate organ's freshness. Nearly a decade and a half later, at his acclaimed French Laundry in the Napa Valley, Keller and several other high-caliber chefs began to experiment with what would become "one of the most important culinary innovations of modern times", using the same principles that underlay the Cryovac system. Essentially, cooking sous vide starts with vacuum-sealing food in plastic. The packages are then immersed in a controlled-temperature water bath that circulates constantly. Precise time and temperature measurements allow certain foods, which would normally be roasted or braised, to achieve distinct textures and uniform temperature, while maintaining flavors and juices that would evaporate when traditional cooking methods are used. Though patisserie and baked goods are nigh impossible to make sous vide, such juicy foods as watermelon and short ribs reach surreal heights, with vivid coloration and seemingly impossible textures. Sumptuously illustrated, the oversize tome is an ode to sous vide "from one chef to another". The recipes are written for a restaurant kitchen and are beautifully layered to mirror the chef's oeuvre.