Publisher: Penguin ISBN 13: 9780141983769. Author: Matthew Walker ISBN 10: 0141983760. Title: Why We Sleep: The New Science of Sleep and Dreams Item Condition: used item in a very good condition. Used-Very Good: The book will be clean without any major stains or markings, the spine will be in excellent shape with only minor creasing, no pages will be missing and the cover is likely to be very clean.