A miniature book is a very small book. Standards for what may be termed a miniature rather than just a small book have changed through time. Today, most collectors consider a book to be miniature only if it is 3 inches or smaller in height, width, and thickness, particularly in the United States.[1] Many collectors consider nineteenth-century and earlier books of 4 inches to fit in the category of miniatures. Book from 3–4 inches in all dimensions are termed macrominiature books.[2] Books less than 1 inch in all dimensions are called microminiature books. Books less than 1/4 inch in all dimensions are known as ultra-microminiature books.[3]