The Opera del Cavalier Francesco Borromini is one of the most important books on Roman Baroque architecture.

Published in Rome in 1720 by Sebastiano Giannini, approximately fifty years after Francesco Borromini's death, it collects engravings from the architect's original drawings and primarily documents the design for the church of Sant'Ivo alla Sapienza. From an artistic and theoretical perspective, the book is crucial because it demonstrates Borromini's design method: an architecture based on complex geometries, dynamic curves, and innovative mathematical ratios, in stark contrast to the more balanced classicism of Gian Lorenzo Bernini. The work also played an important historical role: it contributed to the eighteenth-century rediscovery of Borromini, who after his death had been partly overshadowed by Bernini's fame. The engravings circulated widely among European architects, especially in the German-speaking countries and Central Europe.