Fossils and the doubt they cast on the Biblical story of creation. Why is the sky blue? How does the heart function? What are the differences in air pressure above and beneath a bird’s wing, and how might this knowledge enable man to make a flying machine? Music, military engineering, astronomy. Private notebooks of all sizes, some carried about for quick sketches and on-the-spot observations, others used for long-term, exacting studies in geology, botany, and human anatomy, to specify just a few of the areas in which he posed fundamental questions, and reached answers that were often hundreds of years ahead of his time. These drawings are part of a vast treasury of texts and images, amounting to more than seven thousand surviving pages, now dispersed across several countries and known collectively as “Leonardo’s notebooks”-which is precisely what they were. But it does seem connected with the drawings he made, during the next few years, of two fantastical inventions: a machine that he explained was meant “to open a prison from the inside,” and another for tearing bars off windows. It is impossible to know if this experience affected the artist’s habit, later cited as a mark of his character, of buying caged birds from the market just to set them free. Although any time he may have spent in jail was brief, and the case was dismissed, two months later, for lack of corroborating witnesses, he had plenty of time to ponder the possible legal punishments: a large fine, public humiliation, exile, burning at the stake. There is little doubt that Leonardo was arrested. In 1476, Leonardo da Vinci, on the verge of his twenty-fourth birthday, was named as one of four men who had practiced “such wickedness” with the seventeen-year-old apprentice of a local goldsmith. The common nature of the offense did not erase the threat of serious consequences.

But the crime that the government was really trying to control was sodomy, so notoriously prevalent that contemporary German slang for a homosexual was Florenzer. In Renaissance Florence, a number of designated boxes placed throughout the city allowed citizens to make anonymous denunciations of various moral crimes-in 1461, for example, the artist-monk Filippo Lippi was accused of fathering a child with a nun. Illustration by Tamara Shopsin engraving from Hulton Archive / Getty A new biography celebrates the great artist’s more scientific innovations.

Leonardo da vinci book isaacson