Understanding the electrical failure signature is paramount to effective failure analysis. Defect localization techniques like (Photoemission, IR, OBIRCH/TIVA, SIFT etc.) are excellent tools of choice, however, the analyst must understand when and which of these techniques are applicable. 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.