Vasari’s Lives of the Most Excellent Painters, Sculptors, and Architects is the foundational text of art history, providing biographies of Renaissance artists from Cimabue to Michelangelo. His work coined the term 'Renaissance' and established the idea of artistic progress. As an artist himself, he worked for the Medici family in Florence and designed several notable buildings. His writing remains an essential source for understanding the development of Italian art and the concept of the artist as a genius.