Extreme environment electronics is a research field and engineering discipline focused on developing electronic devices, circuits, and systems capable of reliable operation under conditions far exceeding the typical operational ranges of conventional electronics. This domain investigates the fundamental principles of material behavior, device physics, circuit design methodologies, and packaging technologies specifically adapted to withstand stressors such as extreme temperatures, intense radiation fields (relevant in nuclear environments), high pressure, severe vibration, and corrosive chemical environments. Its significance lies in enabling critical technological advancements and operational capabilities in challenging settings including aerospace, deep-sea exploration, geothermal energy extraction, and nuclear power and research facilities, where standard electronic components would fail.