Claudius Ptolemaeus (circa 100–circa 170), known as Ptolemy, was an astronomer, mathematician, and geographer of Greek descent who lived and worked in the Egyptian city of Alexandria. In his Geography, Ptolemy gathered all the geographic knowledge possessed by the Greco-Roman world. He used a system of grid lines to plot the latitude and longitude of some 8,000 places on a map that encompassed the known world at the height of the Roman Empire. Ptolemy’s work was lost to Europe in the Middle Ages, but around 1300 Byzantine scholars began introducing copies of his maps and writings into Italy. In 1406, the Italian Jacopo d’Angelo translated the original into Latin. The first printed edition appeared in Rome in 1477, followed a year later by the edition presented here, which contains some of the earliest and finest printed copper engravings. The engravings were begun in Rome by the German Konrad Sweynheym, who, with his partner Arnold Pannartz, founded the first Italian press at Subiaco in 1465. Sweynheym died in 1477, and the engravings and the publication were completed by Arnold Buckinck. The work contains 27 maps, each printed on two separate, facing leaves. Ptolemy’s Geography included major inaccuracies, attributable in part to his miscalculating the size of the Earth, which he believed was smaller than it is. One effect of this miscalculation was to cause Columbus to underestimate the time it would take to reach what he thought was Asia by sailing westward. European explorers gradually completed and corrected Ptolemy’s maps, but the ancient geographer’s methods remained important as a basis for modern cartographic practice.