Drawing upon a six-year research project at the Stanford University Graduate School of Business, Collins and Porras took eighteen truly exceptional and long-lasting companies -- they have an average age of nearly one hundred years and have outperformed the general stock market by a factor of fifteen since 1926 -- and studied each company in direct comparison to one of its top competitors. They examined the companies from their very beginnings to the present day -- as start-ups, as midsize companies, and as large corporations. Throughout, the authors asked: "What makes the truly exceptional companies different from other companies?"