This book presents the detailed design considerations and techniques for radiation-tolerant (RT) Nyquist analog-to-digital converters (ADC). It begins with the fundamental radiation effects in space and its consequences in modern CMOS technology. Next, radiation effects on ADCs from the transistor level to the architectural level are examined and a detailed design tradeoffs and strategies for radiation-tolerant ADCs are described. The theory and hardening techniques are supported by measurement data from a high-performance RT-ADC prototype chip. Two important flows, which are a technology evaluation flow and an RT IC design flow, are also covered, in order to give a complete overview on how to achieve an effective RT circuits design.