Book tripe is a type of edible offal made from the stomach lining of ruminant animals, primarily cattle. It is known for its unique texture and is often used in various cuisines around the world. The name "book" refers to its layered appearance, resembling the pages of a book. This ingredient is commonly found in dishes such as tripe soup and tacos de tripas. Before cooking, book tripe must be thoroughly cleaned and often requires long cooking times to become tender. It is a source of protein and is appreciated for its ability to absorb flavors from spices and sauces.