There are two famous artists and architects in the Renaissance era with the name "Giuliano da Sangallo":
* Giuliano da Sangallo the Elder (1445-1516): He was a highly regarded architect who worked on numerous projects in Rome and Florence. He is known for designing the church of Santa Maria dei Miracoli in Rome and contributing to the construction of the Vatican Palace. He also wrote some treatises on architecture, which unfortunately have not survived.
* Giuliano da Sangallo the Younger (1481-1546): He was also a prominent architect, known for his work on the Basilica of St. Peter's and various other projects in Rome. While he did not author books, he left behind numerous drawings, plans, and sketches, which provide valuable insight into his work and the architectural ideas of the Renaissance.
It's possible you are thinking of one of these two famous architects. If you have more information about what you are looking for, please let me know and I can try to help you further.