Oliver Burkeman opens with a stark mathematical framing that gives the book its title: the average human lifespan amounts to roughly four thousand weeks, a genuinely finite and, once calculated, surprisingly small number that reframes how readers might approach time management and life priorities.

Why this stark framing matters:

• Confronting this concrete, finite number counters a common unconscious assumption of essentially unlimited time, which subtly but significantly shapes how people approach priorities and daily choices
• This finite framing motivates the book's broader argument for fundamentally rethinking conventional productivity and time-management approaches
• Burkeman uses this stark calculation as the foundational provocation for the book's subsequent philosophical examination of time and mortality

This opening establishes the book's memorable central framing device, providing motivating context for its broader philosophical challenge to conventional productivity culture.