When St. Bonaventure (1221-1274) was teaching theology in Paris, he was admired by everyone for his great writings. One day, St. Thomas Aquinas went to see him. He asked Bonaventure to show him the books from which he learned so much.

Bonaventure led him into the little room where he studied, and showed him a few ordinary books that lay upon the table. But Thomas told him that he wanted to know the names of the other books that were such a source of his wealth of knowledge.

St. Bonaventure then showed him a little oratory, where there was a crucifix.

"This, my friend, is my only other book." Bonaventure smiled as he pointed to Jesus on the crucifix. "It is the principal one I use, and from it I learn all that I teach and all that I write. Yes, it is in casting myself upon my knees at the foot of the crucifix, and in praying here for light in all my difficulties and doubts, that I have made more progress in the sciences, and have obtained more true knowledge, than I could have done by reading all the books in the world."