The fourth and final volume in Willy Ley's "Adventures in Space" series, Voyage dans l'espace is an encyclopedic panorama of the solar system from the perspective of 1958-era space conquest. Beginning with the fictional interplanetary spacecraft "la Minerve" (set in 1976, launching from the relay station of vol. 3), the book takes the reader through the successive destinations of human exploration: the asteroid Eros (48 km brick shape, 2,000 m/s approach, jetpack landing), Mars and its satellites Phobos and Deimos (calibrated atmospheric data, Schiaparelli's canals), the lunar surface (craters, artificial seismology), then Venus (clouds, supposed synchronous rotation), Mercury (twilight zone), Jupiter (12 moons with detailed table, hypothetical composition), Saturn and the outer planets, comets (comet cloud, "dirty snowball" structure), ending with interstellar distances and the Milky Way.