In the past, integrated circuit errors due to radiation phenomena were negligible, but with continuing technology scaling and low-power requirements, they became magnified to such a degree that they were able to alter the implemented behavior, causing a failure of the whole electronic circuit. In order to increase reliability, general mitigation techniques can be applied. However, those solutions come at a high cost, which, for some applications, is prohibitive but in such cases, custom-tailored ad-hoc techniques can improve the cost. They are difficult to design and their application is not straight-forward. This book develops a systematic workflow for designing ad-hoc techniques. For that, a set of circuits was studied using an inductive process, which led to the identification of common circuit traits. Based on this system knowledge, a novel design methodology has been developed for designing ad-hoc techniques that reduce cost without jeopardizing fault tolerance. For validation, several case studies of ad-hoc techniques have been assessed using the proposed design methodology, showing in each case a significant cost improvement and thereby confirming the proposal.