Book excerpt: Trachtenberg's book exmines the urban transformation of Florence in the fourteenth century. Focusing on the creation of the Piazza della Signoria and the Piazza del Duomo, he documents in engaging detail how and why urban planners, in league with the civic government, enlarged these urban spaces. Articulating the design principles that served as the foundation for these urban renewal projects, Trachtenberg's book fundamentally revises our understanding of urban planning in the early modern period, countering the received claim that rational planning begins only in the Renaissance. His book also brings a new depth of understanding to the entire visual culture of Trecento Florence, demonstrating how many of the developments in painting, sculpture and architecture of this period form the basis of the achievements of the Quattrocento, particularly the discovery of perspective. Combining both empirical and post-structuralist methods, Trachtenberg's book is among the first, if not the first, to question critically many of the assumptions that have formed the basis of scholarship of Renaissance art since the sixteenth century.