This book covers the, methodology and processes required for a successful new product system, component and device development reliability. This book covers introductory definition of reliability terms and gradually build reliability and develop models from components, systems, software reliability and show case study examples of how these methodologies are used was illustrated. This book is the outgrowth of my over 22 years of professional engineering experience in semiconductor industry and systems. This book unlike any other textbook on the subject, presents the processes of reliability engineering conceptually, and with minute details to encourage understanding and assimilation of the material and to show how the concept of reliability is translated from mathematical probability to full product reliability testing. This book bridges the gaps of reliability introduced by the rapid semiconductor advances, process miniaturization, new package and material advances and attempts to shorten new product development, and manufacturing release cycles.