About the book: 1958 / Ultrasounds discovered at the beginning of the 20th century have found wide application in a wide variety of fields of science and technology. They help detect submarines and various obstacles at the bottom of seas and rivers, are used for measuring depths, for quality control of metal structures and parts, for air purification, in the medicine and pharmaceutical industry, etc. About what ultrasonic waves are, about the methods of their production, properties and application are described in the book of a specialist in the field of ultrasound, Professor Doctor of Chemical Sciences Boris Borisovich Kudryavtsev, “On Inaudible Sounds”».