“The Lost Valley” is a work by the French writer, author of numerous “tabloid”, historical and adventure feuilleton novels and dramas E. Berthe (1815–1891). The novel was written in 1851. The battle is over, but who emerged victorious? This is what the residents of Rosenthal did not know, and in the absence of news they indulged in anxiety. Most of them, with their wives and children, were hiding in a shelter near the village. Blue-eyed spinners and lacemakers in their picturesque costumes did not appear on the balconies of houses, and half-naked children did not play on the village street. Is it possible that somewhere a shutter would timidly open to watch a rare passerby hurrying to the other end of Rosenthal with a frightened gaze. At one time the author was more popular than Dumas the Father. Berthe worked in many genres, discovering new themes. His novel “The Orangutan” appeared before E. Burroughs’ “Tarzan,” and “The Coal Miners of Poligny” inspired E. Zola’s novel “Germinal.” The author's books have been translated into many languages, including Russian. Bertha also wrote the following works: “The Beast of Gevaudan”, “The Trembling Rock”, “The Desert Bird”, “The Chauffeurs, or the Gang of Orgers”.