Professor of Biochemistry at the University of Iowa Joseph I. Roth in the book Chemistry of the 20th Century is popular and interesting at the modern scientific level talks about the most important problems of chemistry and its practical application. The book is a lively and at the same time strict exposition of the main sections of modern chemistry. In the first part, after a brief introduction introducing the history of chemistry and its significance, the most important issues of inorganic and physical chemistry are considered. The second and third parts are devoted to the problems of organic and biological chemistry. The book is intended for a wide range of people interested in chemistry. It will be useful for chemistry teachers and secondary school students, as well as for students of non-chemical specialties of higher and secondary educational institutions.