This book explores in depth the essential role of cytochromes P450 (CYP), a family of key enzymes in drug, lipid and steroid metabolism. We trace their history, unique molecular structure and biological functions, including their ability to catalyze complex oxidation reactions. The interactions of cytochromes P450 with other enzymes and metals are examined, highlighting their importance in metabolic pathways. The disorders associated with dysfunction of these enzymes and their impact on pharmacokinetics are discussed, as are their applications in biotechnology, such as biocatalysis and bioremediation. The book concludes with a reflection on future prospects, highlighting the challenges and opportunities for bioinorganics research, with potential implications for the therapeutic and environmental fields.