Selenium WebDriver, developed by Thoughtworks in 2004, is a powerful, open-source tool for automated testing of web applications, offering numerous advantages over its predecessors, Selenium IDE and Selenium RC. Unlike Selenium IDE, which was limited to Firefox and lacked cross-browser support, WebDriver works with a wide range of browsers and supports dynamic website testing, cross-device compatibility, and integration with various testing frameworks like JUnit and TestNG. It operates by mimicking real user interactions on a webpage and provides an object-oriented API that is both user-friendly and adaptable to various programming languages, such as Python, Java, and C#. WebDriver's ability to execute tests across different operating systems and its support for advanced browser interactions and mouse and keyboard events make it an ideal choice for automation testing, particularly for modern, feature-rich websites. Additionally, it does not require starting a server before testing, simplifying the testing process. Despite its complexity compared to previous versions, Selenium WebDriver's flexibility, community support, and cost-effectiveness make it an attractive option for new projects seeking an efficient automated testing suite without the need for paid tools.