Anne Skeldon and Derk-Jan Dijk (Director, Surrey Sleep Research Centre) are co-authors of Chapter 38 of a major two volume book on “Principles and Practice of Sleep Medicine (Seventh Edition)”, published by Elsevier. The book has 2240 pages and 800 illustrations. Chapter 38 is entitled “Sleep homeostasis and models of sleep regulation.” A link to the published version of the book is here.