The underappreciated and I think now entirely out-of-print anarchist philosopher, chief proponent of austeririty in energy and transport, gadfly to the looming post-industrial order of a institutions legitimated and operated by cerdentialed professionals in a regime of "managerial fascism" whose idea of "development" or "progress" is more "education" of the kind which produces more people with credentials at the expense of many many more without them to be managed through radical monopolies of a service culture which not only exploits a consumer's foregotten knowledge of DIY, but exercises jurisdiction over what constitutes legitimate or even possible modes of education, transport, and limits to production-consumption.
Much in the way of rhetoric, Illich is a littls short on empirical matter, although he does provocatively make a call for 'counterfoil research'.
Take Illich with a little salt and a shnot of tequilla, don't dismiss him or laugh at the tumor which he left untreated on his cheek and its cancer which eventually left him dead. He has some novel ideas and unlike a lot of social theorists is PRESENT-FUTURE in orientation, which is probably another reason the academic canon has dropped him. Don't take hime too serious. His comunitas impulse is kind of naive, and Illich's communitarian anarchism has a marked authoritarian streak, although one which does strive toward an articulation of an ethical dimension these days called alterity...