As a sales hook, Adler dreamed up the Index of Ideas, called the Syntopicon, in place of a plain, alphabetical index. A small army of grad students, including the young Saul Bellow, spent seven years in the dusty basement of the Social Science Building compiling what Chicago-educated Joseph Epstein called "the world's largest and most difficult to use index of ideas." Even their friend, Britannica's president William Benton, couldn't abide the ridiculous Syntopicon, which cost over $1 million to create. The first of the 102 officially indexed ideas was "Angel," prompting Benton to object: "Where is ‘Adultery'? Isn't that a Great Idea?" It's under Family, Adler assured him, none too persuasively.

But the real action came in winnowing the great from the nearly great books. Adler and Hutchins didn't know much Greek, so they relied on a colleague to sift through the classics. They knew nothing about science, and imposed on yet another colleague to sort through Euclid's thorny Propositions, to say nothing of Newton's calculus. The Great Books archives are full of Adler's daily swoons, and Hutchins's restrained replies, e.g.: "I must repel the suggestion that I have at any time said that I would read Ptolemy, Copernicus and Kepler. I wouldn't think of such a thing (neither will any purchasers of the Great Books)."

—from A Great Idea at the Time