Mit Raketenkraft Ins Weltall.

Full title Mit Raketenkraft ins Weltenall: Vom Feuerwagen zum Raumschiff (“With Rocket Power into Outer Space: From Fire-Car to Spaceship”), with a foreword by Max Valier and dedicated to Fritz von Opel. Gail — an electrical engineer and mathematician by training, already known for the science-fiction novels Der Schuß ins All and Der Stein vom Mond — had become, in Valier's account, the popularizer he needed: Valier's own 1918 proposal for a rocket aircraft had been ridiculed, his 1923 partnership with Hermann Oberth ended amicably over Oberth's more purely theoretical ambitions, and from the winter of 1925 he found in Gail a “standard-bearer” whose novels won public sympathy for a step-by-step path from airplane to rocket plane to spaceship.

Gail's own introduction recounts being personally invited by Valier and von Opel to witness the first test runs of what he calls the world's first powder-driven rocket vehicle, on the Opel racetrack at Rüsselsheim in April 1928; one of the book's photographic plates, showing the rocket car mid-run trailing smoke, is credited as the author's own photograph.

The book then surveys the wider rocket-research scene as of 1928 — Oberth and Walter Hohmann's mathematics, Franz von Hoefft's Gesellschaft für Raumforschung in Vienna (founded 1926), and Johannes Winkler's Verein für Raumschiffahrt in Breslau (founded 1927, publisher of the journal Die Rakete), with portrait plates of Oberth and von Hoefft — and lays out the core difficulty of the space rocket itself: the fuel-mass ratio needed to reach the roughly 11,200-meter-per-second escape velocity, and the enormous energy cost of lifting each kilogram of payload off the Earth. It closes with an illustrated speculative narrative imagining a future crewed rocket's launch and its eventual parachute landing over New York.