On behalf of myself and my fellow Guest Editors for the Special Issue on Ultra Wide Band Gap Semiconductors for Power Control and Conversion appearing in this month’s issue of the IEEE Transactions on Electron Devices, we are gratified to be able to present readers with a selection of papers spanning the current state of the art in wide and ultrawidebandgap semiconductor devices. Electronics for power control and conversion is presently going through a renaissance, with new device concepts, extensions of known concepts to new materials, and new applications all merging simultaneously. Fundamental material-level work in Ga2O3, diamond, Al(Ga)N, and other ultrawidebandgap materials have begun to produce device results commensurate with the fundamental advantages that these materials promise for power control and conversion applications. At the same time, the understanding and performance of devices based on SiC and GaN continue to improve. Applications of these new materials and devices include automotive, data center power management, grid control, industrial and locomotive traction control, and others. Despite the tremendous progress in this area, however, much remains to be understood. The role of intrinsic and extrinsic defects in these materials on device performance, optimal strategies for device design and fabrication, surface passivation, and dielectric materials suitable for the high electric fields supported by these materials, device structures, and concepts for achieving the best possible electrical performance, appropriate approaches to thermal management, and the potential and challenges of integration of these devices with other semiconductors for system implementation are all areas in which rapid progress is being made.