 Such instruments included tools like forceps, pincers, scalpels, catheters, cauteries, lancets, and specula, which were accompanied by detailed drawings of each tool.Al-Zahrawi also wrote the "At-Taṣrīf limanʿajazʿan at-Taʾālīf," or "At-Taṣrīf" (“The Method”), which was a 30-part text based on earlier authorities, such as the "Epitomae" from the 7th-century Byzantine physician Paul of Aegina.It was largely composed of medical observations, including what is considered the earliest known description of hemophilia.