Nilo-Saharan-speaking desert people of the Tibesti massif and the oases south and east of it, split into the northern Teda and the more numerous Daza. Clan-based rather than state-organised: clans hold priority rights over named palm groves, wells and pastures, and the only trans-clan authority is the derde, an elected arbiter drawn from the Tomagra clan who judges disputes by a code of compensations rather than commanding. Teda-Daza speakers were the nomadic stock from which Kanem's founding confederation was drawn, and Toubou clans taxed and raided the Bilma–Fezzan salt and slave route for a millennium after.
Not an ending: French forces entered the Tibesti in 1913–14, abandoned it in 1916 and only returned in the late 1920s, with permanent garrisons from 1932 — the derde and the clan system survived colonial rule intact. Toubou remain the dominant people of northern Chad, southern Libya and north-eastern Niger, and have supplied several Chadian heads of state.
The standard collective volume on Toubou society specifically — social strata, clan land rights, the derde and the Tibesti/Ennedi divide; parts are open-access on OpenEdition.
The classic monograph on the Toubou; the Library of Congress Chad study cites Chapelle by name as its authority on Toubou social structure.