Manual testing is the process of manually testing software for defects by playing the role of an end user and using all features of the application to ensure correct behavior, following a written test plan. The document discusses various concepts related to manual testing including software quality assurance, verification, validation, software life cycles, testing techniques like black box testing and white box testing, unit testing, alpha testing, beta testing, system testing, volume testing, stress testing, and security testing. It provides brief definitions and purposes of these concepts.