By the late 1920s, rocketry had moved from the writings of isolated visionaries to an organized, international pursuit. In Germany, the Verein für Raumschiffahrt (VfR, or “Society for Space Travel”) gathered engineers, students, and amateurs around the shared conviction that spaceflight was an engineering problem, not merely a literary one. Willy Ley, a young science writer and founding member of the VfR, became one of its most effective popularizers.

Ley’s Die Fahrt ins Weltall (1926), cataloged elsewhere in this collection in its signed first edition from N.A. Rynin’s library, went through a second, fully revised edition in 1929. The copy shown here is inscribed by Ley in Berlin on May 5, 1929, “with compliments from the author,” to the same Rynin — a Russian engineer and historian of spaceflight corresponding across the era’s political divides in pursuit of a shared idea.

That same year, the Austro-Hungarian engineer Hermann Noordung (Herman Potočnik) published Das Problem der Befahrung des Weltraums, the first technically detailed proposal for a habitable space station. His wheel-shaped “Wohnrad,” designed to rotate for artificial gravity, anticipated station concepts still used in science fiction and engineering studies today.

Underlying both men’s work was the orbital mechanics formalized in 1925 by Walter Hohmann, whose Die Erreichbarkeit der Himmelskrörper is also in this collection. The two-burn transfer orbit he described — still called the “Hohmann transfer” — remains the standard low-energy method for moving a spacecraft between orbits.