Lyon's account of a trans-saharan expedition in Northern Africa, which left from Tripoli in 1818, describes the caravans of the trans-saharan slave trade that he encountered during his travels, and gives an eye-witness narrative of the ill-treatment of slaves, who were often beaten or left behind if they could not walk at the pace of the caravan. He also gives a brief account of practices of slavery in the area, particularly in chapter seven, which describes the Fezzan region (now southern Libya) and the legal regulations of slave ownership there.