Main and the most famous work by Paul-Henri Thiry, Baron d'Holbach, a French-German author, philosopher, encyclopedist and a prominent figure in the French Enlightenment. “The System of Nature” appeared in 1770, and offered a detailed substantiation of materialism and atheism of the epoch. It was called a “bible of materialism, but convicted by Parisian parliament and condemned to burning with all the atheistic works of the author. Holbach, however, escapes punishment, prison, or, perhaps, death, since even close friends were not aware of his authorship. Here the author systematically presented his Weltanschauung: he said that nature is the cause of everything and will exist eternally. Nature was for him an immense and continuous chain of cause and effect, where everything happens just owing to necessary reasons. He denied any accidental coincidence, considering it to be consequence of ignorance of cause.