The hydrosilane/potassium tert-butoxide reagent system has attracted significant attention over the last 5 years since the discovery of its ability to silylate heteroarene C–H bonds. Numerous useful HSiR3/KOtBu-mediated transformations are now known, including silylation of sp, sp2, and sp3 C–H bonds, reductive cleavage of C–O, C–S, and C–N bonds, reduction of polycyclic arenes, and hydrosilylation and polymerization of styrenes. This mini-review surveys the rich diversity of reaction mechanisms, both ionic and free radical and including hydride transfer, H atom transfer, and electron transfer, that have been uncovered during recent studies on the HSiR3/KOtBu reagent system. Several mechanistic phenomena that remain to be explained are also highlighted.