The 4-Hour Workweek: Escape 9-5, Live Anywhere, and Join the New Rich is a 2007 self-help book by Timothy Ferriss. It advocates for 'lifestyle design' and provides strategies for increasing productivity, automating income, and maximizing free time.
Tim Ferriss have been harping on about it for years
""Tim Ferriss is mentioned as someone who has been 'harping on' about Athletic Greens, and later in the transcript, his book is explicitly referenced. This is his most iconic work."