National Cookie Day on December 4th celebrates the cookie. Outside of the U.S., most people refer to cookies as a “biscuit.” A cookie is a baked or cooked dough that is small, flat and sweet. It usually contains flour, sugar and oil or fat. People often add raisins, oats, chocolate chips or nuts. From classic chocolate chip to creative new flavors, these cookbooks are your go-to guide for all things cookies.