Al Ries and Jack Trout's positioning theory, first published in 1981, remains the foundation of modern marketing strategy. Positioning is not what you do to a product — it is what you do to the mind of the prospect. This article distills the core principles: owning a word in the customer's mind, the power of being first, the ladder of categories, and repositioning the competition. It updates these principles for the digital age where attention is scarcer than ever and demonstrates how startups and incumbents alike can win the positioning game.