Other things make the world go round as well—love, principally, and coffee—but there is nothing quite like the study of business to illuminate where we have been and where we are going. The poet Archibald MacLeish, when he was a staff writer at Fortune, described his job as to “report the world of business as an expression—a peculiarly enlightening expression—of the Republic, of the changing world.” It has become a bit of a catchphrase among tech people to say that one’s company is going to “change the world.” Many companies do, in small ways. But disrupting, say, the taxi business is not going to set future historians atwitter (though Twitter conceivably might). We surveyed Fortune’s brain trust to come up with a ranking of the 27 companies that have done the most to alter the way we live. Then, of course, we couldn’t stop. So when you’ve considered this compilation, click through to two companion pieces, 11 quirky companies that totally blew your mind, and 20 companies that changed the world—in fiction.