ABSTRACT
Here is evidently just the moment for an autobiographical remark. I graduated from the physics faculty of Moscow State University in 1938 as a specialist in optics but immediately changed to theoretical physics-quantum electrodynamics, the theory of higher spin particles, etc. But when in 1941 the war broke out, I , like many of my colleagues, began looking for an application of my efforts in a more practical field and so, rather occasionally, I devoted myself to radio-wave propagation in the ionosphere. These studies, together with other topics, occupied me over many years and the results are summarized in [6]. It was the work on radio-wave propagation in the ionosphere that brought me to radio astronomy.
