It’s hard to overestimate the influence Ted Levitt’s “Marketing Myopia” has had on the world of marketing and beyond. Like Harold Bloom’s Anxiety of Influence in literary criticism or Donald Norman’s The Design of Everyday Things in product design, Levitt’s half-century-old treatise on examining what business your company is really in hovers over and continues to influence entire schools of thought. Frequently repackaged (by us — here’s one example — and others) and incessantly cited, “Marketing Myopia” offers a way to approach everything from libraries to thinking green. Its impact as a concept has weighed on generations of innovators: it’s hard to imagine marketing malpractice without this antecedent.