It was Remy's favorite book and a very important inspiration for him as he followed his love of cooking. Remy stole the book from the old lady that the clan lived with. When he was in the sewer, Remy "talked" to Gusteau through this book.
Anton Ego hated the book, believing that not anyone can cook. He later accepts it, interpreting its motto as: "Not everyone can become a great artist; but a great artist can come from anywhere."
When Colette hears Linguini's claim that the Remy is the real cook. Tearfully, she is unable to believe that Linguini who was considered one of the best chefs in Paris has been taking credit for the work of a lowly rat and so leaves him. However, she sees the book in a store window and remembers Gusteau's motto: "Anyone can cook," in which she believes in, and returns to aid Linguini and Remy in the cooking.