Magnetism in solid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$: Confrontation between theory and experiment

A summary of the current understanding of nuclear magnetic ordering in solid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ is presented. The main emphasis is a critical review of what is known from the experiments along with a critique of various theoretical models. Unanswered questions are raised about both the macroscopic phenomena and the microscopic origins of the magnetism. Several experiments are proposed which should help advance our understanding of the magnetic behavior of solid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$.