This paper reviews the state of current electronics and states the drive toward high-temperature electronics. The problems specific to high-temperature effects on conventional electronics and prospects of alternative technologies like silicon-on-insulator, silicon carbide, and diamond are discussed. Improving petroleum recovery from oil wells with high-temperature coverage of downhole electronics, making combustion processes more efficient utilizing embedded electronics, programs for More Electric Aircraft and Vehicles necessitating distributed control systems, and environmental protection issues stress the need to use and develop high-temperature electronics. This makes high-temperature electronics a key-enabling technology in the 21st century. Actual applications using high-temperature electronics are discussed in some details. Also information and guidelines are included about supporting electronics needed to make a complete high-temperature system. The technology has been making major advancements and is expected to account for 20% of the electronics market by 2010. However, many technical challenges have to be solved.