Ottoman imperial administration could not have functioned efficiently without the documents produced by the central secretarial service, from everyday registers of appointments, orders resolving disputes, and financial records, to imperial correspondence at the highest levels. To be a katib (secretary) in the imperial council was a crucial role. From a surprisingly small, relatively inconspicuous number in the early sixteenth century, the central secretarial body grew in size and significance until by the eighteenth century the bureaucracy had become a recognized third arm of government, alongside the military and the judiciary; it provided essential ministerial leadership in the nineteenth-century reform movement. Focusing on a critical period of change from the mid sixteenth to the mid seventeenth centuries, this chapter introduces aspects of secretarial recruitment, training, and output, concluding with a comparison of two major letter collections, one compiled c. 1574 by the reisülküttab (chief secretary) Feridun Bey, the other c. 1640 by a later reis Sarı Abdullah (d. 1660).