The German ethnologist and explorer Theodor Koch-Grunberg (1872-1924) discusses the origin and significance of rock art in South America in this study, originally published in 1907. In the first part of the book Koch-Grunberg traces the earliest mention of Brazilian rock art to an eighteenth-century German explorer and gives a wide-ranging account of rock paintings found in South America, engaging critically with the interpretations proposed by some of his fellow scholars. In the second part of the work, the author reproduces (either as drawings or photographs) 29 rock paintings that he himself discovered during one of his expeditions to the Yapura River and the Rio Negro (Venezuela) in 1903-1905. He comments on the characteristics and significance of each of the paintings and assesses their impact within the larger ethnological context of the indigenous tribes of that area.