Complete techniques is a combination of 4 indispensable volumes of Jacques Pépin. I have had "La Technique" and "La Methode" from the time that they were first published, and I bought Pépin's "A French Chef Cooks at Home" shortly thereafter. When "The Art of Cooking Volumes 1 and 2" came out, it was a natural addition to my cooking library. I can think of no other books (sorry Julia) that are as clearly written with step-by-step instructions and photography as Jacques's landmark works that teach elementary through advanced techniques.
This one comprehensive volume will allow any neophyte to become an accomplished star in their kitchen, and produce results that are both visually stunning, and gustatorily impressive. A must have for any aspiring chef, and a great resource for an experienced one.