Hannah Ostroff writes: “Library of Congress collections hold some 40,000 cookbooks, plus thousands of recipe booklets, archival recipes and dietary therapy books, that reflect America’s holiday food traditions—a seasonal smorgasbord of ingredients, techniques, technology and culinary viewpoints. McCall’s Book of Merry Eating, published in 1965, offers multiple recipes for [gelatin-based] so-called salads, to be chilled in a mold and served over salad greens. One contains canned corn, a package of frozen peas and carrots and chicken bouillon.”