Agostino Vespucci's De situ, longitudine, forma et divisione totius Hispaniae libellus represents one of the first, most thorough and lively Renaissance descriptions of Iberia. Combining the genres of chorography, travel literature and the diplomatic report, the book deals with the country's geography, ethnography, recent history and Roman antiquities, merging the past with the present and having recourse to both literary sources and the author's own investigations. As Vespucci's only extant literary work, it sheds light on his humanist activity and political ideas, and it allows us to assess the influence that figures such as Poliziano and Machiavelli exercised on him. The manuscript treatise, which was dedicated and presented to Cardinal Giulio de' Medici (later Pope Clement VII) in 1520, is edited here for the first time.