The author of this book, Nikolai Aleksandrovich Bernstein (1896 - 1966), is an outstanding scientist, corresponding member of the USSR Academy of Medical Sciences, laureate of the USSR State Prize, the creator of a new direction in science - the physiology of activity, the discoverer of a number of its laws.

The book was created in the late 1940s. But it did not see the light of day: its author was accused of cosmopolitanism, vulgarism, and the creation of pseudoscientific theories, and the book was not allowed for production. And now this work falls into the hands of readers for the first time. Although more than four decades have passed since it was written, it is modern and in many ways still original.

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