For years I have collected vintage party cookbooks, relishing in the sometimes timeless and sometimes hilariously dated advice they provide to aspiring hosts. While I was writing Party Tricks, my own entry into the genre, I was haunted by a quote from the introduction to James Beard’s 1940 book Hors D’Oeuvre and Canapés. “The cocktail party no longer means a bottle of gin, a can of sardines, and a...