Kent Beck is a prominent software engineer and one of the original signatories of the Agile Manifesto. He is best known for developing the concept of Extreme Programming (XP), which emphasizes customer satisfaction, flexibility, and frequent releases of small, functional software updates. His work has significantly influenced modern software development practices. In addition to his contributions to XP, Beck is also recognized for his role in creating the JUnit testing framework, which has become a standard tool for unit testing in the Java programming language. His ideas and methodologies continue to shape the way software is developed and tested today.