David Allen first published his book "Getting Things Done" in 2001, which is still relevant today. His methodology, GTD, emphasizes the importance of creating a system that allows individuals to unload their thoughts and ideas, and find clarity through this process. Allen believes that productivity is not about working harder or faster, but rather about creating space and clarity to be present with whatever one is doing. He also stresses the importance of reflection time and taking breaks to rest the brain. GTD has been adapted by many individuals and groups, and its principles apply universally, regardless of age or profession. Allen's work has influenced the development of various productivity tools and apps, but he believes that AI-powered systems are not yet ready to fully support GTD. Ultimately, an ideal system would integrate all relevant information and allow for seamless connections between different data points, making it easier to stay organized and focused.