The non-Riemannian dislocated crystal: a tribute to Ekkehart Kr\"oner (1919-2000)

This expository paper is a tribute to Ekkehart Kr"oner’s results on the intrinsic non-Riemannian geometrical nature of a single crystal filled with point and/or line defects. A new perspective on this old theory is proposed, intended to contribute to the debate around the still open Kr"oner’s question: “what are the dynamical variables of our theory?”