In November 1895, the German physicist Wilhelm Rontgen discovered X-rays while experimenting with electrical discharge tubes known as Crookes tubes in his laboratory at the University of Wurzburg in Bavaria. He noticed that a nearby fluorescent screen glowed even when shielded from the tube's visible light, revealing an unknown form of penetrating radiation produced by electrical discharge. His first X-ray image, showing the bones of his wife's hand, astonished the world and earned him the first Nobel Prize in Physics in 1901.

The discovery of X-rays, invisible radiation produced by electrical discharge that could see through solid matter, had an explosive impact on the literary imagination of the fin de siecle. The ability to peer beneath surfaces resonated with the period's literary preoccupation with hidden truths, psychological depth, and the dissolution of appearances. Thomas Mann's "The Magic Mountain," with its X-ray imagery of characters' internal structures, is the most profound literary engagement with Rontgen's discovery, and the X-ray became a pervasive metaphor in modernist poetry for the poet's ability to penetrate beneath the surface of experience.