This post draws your attention to three book-length studies published on Islamic law as preserved in documents from the courts of Ajdābiya and Kufra, two cities that are home to mostly sedentarized Bedouin. The cases preserved in those court archives date from the 1930s to the 1970s—thus the studies reveal the nature of the interaction between law and custom as it was in mostly nomadic but sedentarizing societies, as opposed to how it is now.
Layish, Aharon. 1991. Divorce in the Libyan Family. A study based on the sijills of the sharī‘a courts of Ajdābiyya and Kufra. New York: NYU Press.
Layish, Aharon. 1998. Legal Documents on Libyan Tribal Society in Process of Sedentarization. A selection of decisions from the sijills of the sharī‘a courts of Ajdābiya and Kufra. Part 1: The documents in Arabic with a glossary of Arabic legal terms and phrases, with an anthropological critique by John Davis. Wiesbaden: Harrassowitz.
Layish, Aharon. 2005. Sharī‘a and custom in Libyan tribal society. An annotated translation of decisions from the Sharī‘a courts of Ajdābiya and Kufra, with a linguistic essay by Alexander Borg. Leiden: Brill.