This review is devoted to the famous Dutch scientist Balthasar van der Pol, who made a significant contribution to the development of radioengineering, physics and mathematics. The review outlines only one essential point of his work, associated with the equation that bears his name, and has a surprisingly wide range of applications in natural sciences. In this review we discuss the following matters.
• The biography of van der Pol, history of his equation and supposed precursors.
• The contribution of A.A. Andronov in the theory of selfoscillations.
