Yakov Perelman was a Russian scientist and exponent of recreational mathematics whose stature in his own country was, and remains, similar to that of Martin Gardner in the United States. Between 1913 and his death, Perelman authored a dozen books and scores of articles covering many different aspects of popular mathematics, physics, and astronomy. His books have been republished so often in Russia, that Perelman is universally known among both amateur and professional mathematicians across several generations. He was also a leading proponent of the ideas of the spaceflight visionary Konstantin Tsiolkovsky.