Since the first days of community life, human beings have used different plant species for food, fodder, construction materials, fuel, dyes and treatment of diseases, among other applications. The Lamiaceae family is one of the most important plant families that includes many species that people use for various purposes in their daily life. Origanum contains several species commonly used as spices and tea for medicinal purposes, and is one of the most commercially important genera within the family Lamiaceae. In this book, the genus Origanum is introduced in seven chapters in detail. Taxonomy of Origanum is given in the first chapter, pollen characteristics are given in the second chapter, phylogeny, biogeography and character evolution are given in the third chapter, cultivated species, suitable varieties for agriculture, yield and quality characteristics, and harvesting processes are given in the fourth chapter, secondary metabolites (monoterpenes, phenolics, flavonoids, diterpenes etc.) are given in the fifth chapter, biological activities (antimicrobial, antiviral, antifungal, antioxidant, anti-inflammatory and antidiabetic activity) are given in the sixth chapter, and finally the traditional uses and prescriptions, pharmacology, commercial and economic importance of the genus are given in the seventh chapter.