It is almost impossible to localize a defect physically unless the approximate failure site is known. Defect localization techniques like (Photoemission, IR, XIVA etc.) are excellent tools of choice. However, there are certain failures that are not amenable to such techniques. The only option in such cases is ‘electrical localization'. The classic case studies compiled in this tutorial are based on the tools techniques and the philosophy of analysis utilized in each case study. We will discuss a scenario where several test tools and strategies are utilized to localize the failure before physical failure analysis is carried out.