Instead of asking 'How do I succeed?' inversion asks 'How would I guarantee failure?' and then avoids those things. Used by Charlie Munger, Carl Jacobi, and countless other great thinkers, inversion is one of the most powerful yet underused mental models. This article explains the mathematics of inversion, provides historical examples (how Munger uses inversion in investing, how Amazon uses it in strategy), and offers practical exercises for applying inversion to product development, hiring, organizational design, and personal decision-making.