Space Rocket Trains.

The first work Tsiolkovsky devoted entirely to the multi-stage “rocket train” concept, and the fullest mathematical exposition of his staging theory, though the underlying idea appears in his own 1911–1912 writings and Robert Goddard had already patented rocket staging in the U.S. (1914). 38 pp., portrait frontispiece, with a biographical sketch of Tsiolkovsky by S. V. Bezsonov. Print run of 2,000 copies per the colophon.