On the cover

Cacio e pepe is a popular Italian pasta dish whose rich, velvety sauce is made of an emulsion of pecorino cheese and black pepper. Cooking a cacio e pepe sauce that deliciously clings to each piece of pasta is not just a culinary achievement but a scientific one. To learn how the physical properties of pasta ingredients interact to make the perfect sauce, read the Quick Study by Daniel Maria Busiello, Vincenzo Schimmenti, and Ivan Di Terlizzi. (Photo by Simone Frau.)