The book "Natural Production of Organohalogen Compounds" provides a comprehensive summary of current knowledge about naturally occurring organohalogen compounds, of which more than 3,700 are documented. It addresses all aspects of this field, including the structural diversity and sources of organohalogens, as well as the mechanisms of their formation and biodegradation. Special attention is given to the clinical use of dichloroacetate and the synthesis of the effective anticancer drug chlorinated cryptophycin. The work highlights both biogenic and abiogenic sources of organohalogens, including volcanic emissions and abiotic formation in soil. Additionally, specific chapters are dedicated to halogenation in humans, fungi, and the ocean. Another focus is on the sources and biosynthesis of the relatively rare natural organofluorines. By gaining a better understanding of the role that nature plays in the field of organohalogens, we can more intelligently regulate the production, use, and disposal of artificially produced organohalogen compounds.