Book excerpt: A comprehensive and detailed overview of the current state of preclinical research on histamine and histamine receptors. Part of the book focuses on novel approaches to the study of histamine receptors such as polymorphism, genetic linkage, and computational analysis, and on the use of new histaminergic ligands in diseases such as asthma and dermatitis. Several chapters will be devoted to the role of histamine in the control of homeostatic and behavioral responses such as the sleep-wake cycle, regulation of the blood brain barrier, food intake, alertness, itch, and memory formation and consolidation.