The Book of the Courtier remains the definitive account of Renaissance court life. Because of this, it is considered one of the most important Renaissance works.

The book is organized as a series of fictional conversations that occur between the courtiers of the Duke of Urbino in 1507 (when Baldassare was in fact part of the Duke's Court). In the book, the courtier is described as having a cool mind, a good voice (with beautiful, elegant and brave words) along with proper bearing and gestures. At the same time though, the courtier is expected to have a warrior spirit, to be athletic, and have good knowledge of the humanities, Classics and fine arts. Over the course of four evenings, members of the court try to describe the perfect gentleman of the court. In the process they debate the nature of nobility, humor, women, and love.