This book is designed keeping job interviews in mind. We proceed based on interview questions.Here we will be discussing the theoretical basis of testing. This book covers questions from basics to advanced topics, traditional testing approaches to the latest trends in software testing.This is for anyone who is preparing for interviews for software testing jobs. This is for anyone who want to pursue a new career in software testing, or want to strengthen their fundamentals in this field.We will start our discussion with a quick introduction to software testing. We discuss why is it important, principles of software testing, and key skills required in this field. There are different ways to group, or classify software testing methods or approaches. We will discuss commonly used classifications and types of testing. We will discuss test scenarios and learn to write test cases. There are lessons on defect life cycle and its classifications.There are modules on traditional testing approaches, and new approaches like test driven development or TDD, acceptance test driven development or ATDD. We will discuss all these, and there will be an introduction to Model Driven Development and model-based testing.Along with this, a list with different types of testing and short descriptions, which are not covered in other modules are provided at the end of this book.