Born in Brussels in 1856, he wrote in French in collaboration with his younger brother, Séraphin Justin François Boex, under the joint pen name J.-H. Rosny until 1909.

Because his writing was not translated into English before his death, and his readers did not always understand his science fiction novels, his impact on the early evolution of the genre was limited.

In the story, which takes place a thousand years before Babylonian times, primitive humans encounter inorganic aliens, with whom all forms of communication prove impossible.

The story "Un Autre Monde" ["Another World"] (1895) establishes that humans share the Earth with the land-bound Moedigen (Dutch for 'brave ones') and the air-borne Vuren ('fires'), two infinitely flat and invisible species who cohabit with us.

Rosny's masterpiece is Les Navigateurs de l'Infini [The Navigators of Infinity] (1925) in which the word astronaut, "astronautique", was coined for the first time [citation needed].

In the story, Rosny's heroes travel to Mars in the "Stellarium", a spaceship powered by artificial gravity and made of "argine", an indestructible, transparent material.