For many enzymes, the catalytic function is dependent on the presence of the specific cofactor which, in most cases, is a trace element or a derivative of a water-soluble vitamin. The book is addressed to biology, chemistry, medical and master students, but also to doctors and specialists who want to have a concise view on the fundamentals underlying enzymatic cofactors and vitamins. It also aims to briefly circumscribe aspects related to the mechanisms of action of enzymatic cofactors and the role of vitamins in the human body.