Gary Keller and Jay Papasan open The One Thing by introducing their central practical tool: the "focusing question" — "What's the ONE Thing I can do such that by doing it everything else will be easier or unnecessary?" — arguing that consistently applying this question is what distinguishes extraordinary results from merely good ones.

Why this specific question structure matters:

• The question's specific phrasing — "such that by doing it everything else will be easier or unnecessary" — forces identification of genuinely high-leverage priorities, rather than simply the most urgent or immediately appealing tasks
• This differs from typical prioritization approaches that treat all tasks on a to-do list as roughly comparable in importance, instead demanding identification of the single task with outsized, cascading impact on everything else
• The authors argue most people's daily activity consists largely of tasks that feel productive but don't actually meet this high bar of genuinely enabling everything else to become easier or unnecessary

This foundational question sets up the book's overall practical framework: applying this same focusing question across multiple time horizons — daily, weekly, life-scale — to consistently identify and prioritize genuinely high-leverage activity over merely busy activity.