Otto Lyudvigovich Struve (1897–1963) was a renowned Russian-American astronomer and geophysicist who had worked at the University of Chicago and University of California. He was the Director of Yerkes Observatory (USA) in 1932–1947 and member of the National Academy of Sciences since 1937. This publication consists of two letters written by the scientist to his relative, Alexei Petrovich Struve. One of these letters contains, among other things, O. L. Struve’s brief personal history. The letters were kindly provided for publication by A. P. Struve’s son, Nikita Alexeyevich Struve.