“In collecting such a medley of ideas, Leonardo was following a practice that had become popular in Renaissance Italy of keeping a commonplace and sketch book, known as a zibaldone. But in their content, Leonardo’s were like nothing the world had ever, or has ever, seen. His notebooks have been rightly called “the most astonishing testament to the powers of human observation and imagination ever set down on paper.” The more than 7,200 pages now extant probably represent about one-quarter of what Leonardo actually wrote,4 but that is a higher percentage after five hundred years than the percentage of Steve Jobs’s emails and digital documents from the 1990s that he and I were able to retrieve. Leonardo’s notebooks are nothing less than an astonishing windfall that provides the documentary record of applied creativity.”

Excerpt From: Walter Isaacson. “Leonardo da Vinci.