The rock art sites of the Tadrart Acacus in southwestern Libya were inscribed on the UNESCO World Heritage List in 1985, largely owing to the activities started in 1955 by Fabrizio Mori, founder of the Libyan-Italian Mission in the Tadrart Acacus and Messak. Since the beginning, the Department of Antiquities of Tripoli and Sebha, Libya, and Sapienza University of Rome, Italy, have worked in the region nearly without interruption until 2011. This book presents the archive of the rock art sites, identified and recorded by the Italian Mission and by independent scholars, as described and critically assessed by the authors within the framework of the ASArt-DATA project (the European Union’s Horizon 2020 research and innovation programme). The contributions introducing the catalogue contextualize the environmental, archaeological, and cultural aspects of the engravings and paintings. They include chapters addressing the historical, cultural, and diplomatic issues involved in the long-term bilateral scientific cooperation.