This chapter provides demographic information on the number of Hausa speakers and their geographical distribution. The geographic core of traditional ‘Hausaland’ is the area encompassing Zaria, Kano, and Katsina. Hausa is classified as a Chadic language belonging to the West-A branch. It constitutes a group by itself along with a Creolized offshoot called Gwandara. Hausa employs two writing systems dating from the beginning of the twentieth century, one using the Latin alphabet (called boko), the other using the Arabic alphabet (called ajami). Hausa linguistic scholarship over the past century and a half is outlined, including that of Hausa-speaking linguists in Nigeria and Niger in recent times. This work has been mostly descriptive. The foundation for the historical study of Hausa is a classic paper published a century ago by August Klingenheben.