This may surprise you. This may disappoint you. This may shock you.
But. My vote for the single best cookbook you must have is...
The Joy of Cooking, 1975 edition.
Why not an Italian cookbook? Italians do not have our tradition of writing and using cookbooks, precisely because they are better at cooking. If you were to read their recipes, you would see a much greater vagueness, with expressions like "place in very hot oven till done". This also implies a higher level of skill. Marcella Hazan, for one, is not at all well-known in Italy. Hazan is basically an interpreter, and a good one, of the Italian gastronomic tradition to the Americans.
