In the 17(th) Century, Roman construction techniques attained unrivalled results, derived from experimentation carried out in the greatest building sites of the Renaissance. Such was the success that the so-called "Roman construction system" became an effective, fast and technologically advanced working method that lasted, basically unchanged, up to the 20(th) Century. Baroque building practices hide a number of secrets and devices which not only represent an extraordinary preview of some present construction techniques, but also contribute to clarify the reason for the lasting effectiveness of these traditional construction methods. Among the most popular techniques of the Roman Baroque building practices, we have the methods used to lengthen the setting time of masonry mortar, strongly recommended by Francesco Borromini; the use of special mechanical devices; the stratagems introduced in brick manufacture and laying; the special procedures followed in the supply and the working of lime, plaster and freestone.