Walter Isaacson's Leonardo da Vinci (2017) might be the best work of history I have read in the past year. I approached this book with trepidation, because Isaacson is not a historian. He is a technology groupie whose previous biographies have focused on much more modern characters like Steve Jobs, Henry Kissinger, and Albert Einstein, and I feared that without sufficient knowledge of the sixteenth century he would get everything wrong. He did not. He put in the effort to learn enough about Renaissance Italy to put Leonardo in his context, and the result is a terrific book.
Isaacson approaches Leonardo mainly through his notebooks. This is probably the best way for a biographer to proceed, because it is only in the notebooks that Leonardo's distinctiveness really emerges. Yes, he did a handful of amazing paintings, but in an era when other men did equally amazing paintings. His modern fame derives from his polymorphic genius. One might even say that it derives from a belief in genius as a powerful force in itself; it is as an exemplar of genius and a proof that a genius is a recognizable and important thing that Leonardo looms in our consciousness.
We know about Leonardo's ideas mostly from his notebooks. Very little that he imagined was ever published in any other form, let alone actually constructed, so if the notebooks had been lost, so would all record of his genius. Leonardo was a compulsive sketcher and note-taker, and scholars think he created about 13,000 pages of notebooks, more than 7,000 pages of which survive. It makes me wonder; how many other people were creative in this same way, but we don't know because their notebooks don't survive?
We can certainly see that Leonardo was a man of his time, interested in things that also fascinated his contemporaries. For example, perspective in vision and painting, one of the many topics about which Leonardo considered writing a book that he never finished.
Leonardo da Vinci (1452-1519) was certainly a remarkable person. He was the illegitimate son of a provincial lawyer, with no great prospects but on the other hand without any pressure to fill his father's shoes. Since he showed an early talent for art he was apprenticed at he age of 14 to Verrocchio, who ran one of the top artistic workshops in Florence. Since Leonardo's own lifetime art lovers have made a game of guessing which bits of Verrocchio's paintings were by Leonardo, and while some of those guesses must be right, I don't think any are certain. Leonardo was certainly developing as an artist, as the teenage drawing above shows.
Leonardo began completing his own commissions around 1480. He was already a hanger on of the unofficial Medici court -- at that time Florence was a Republic, and the Medici its first citizens -- where he played music and sang as well as painting. At the court he presumably had his first exposure to classical learning, and his first experience of being snobbed off as a rustic because he did not know Latin or anything about the ancient world. Leonardo's immediate reaction was to denounce book learning and to proclaim that experience was the only real source of knowledge. As he got older he began to see some value in scholarship and tried to learn Latin, but he was never very well educated by the standards of his time.
In 1482 Leonardo moved from Florence to Milan, where he entered the service of the mercenary captain turned ruler Ludovico Sforza. Sforza was a thug but the atmosphere of the court agreed with Leonardo. He was already bored with painting and longed to stretch his talents in other directions, and he hated all the committee meetings and expense audits that went with working for a Republic. One of the best things Isaacson does in his book is to show the importance of the connections that Leonardo made to other artists and intellectuals in Milan. For example, the famous drawing of Vitruvian Man emerged from a collaboration with two other men to design a new crossing tower for Milan's cathedral. While working on their design the three men discussed the ideas of the ancient Roman writer Vitruvius, who taught that the proportions of a building should reflect those of the human body. The three men discussed how to design a church according to these principles and all three produced their own drawings of a perfectly proportioned body for use in making the calculations. Leonardo's drawing is of course the best, but it was through working with other men that he came to understand this issue and develop his own version.
To me the most extraordinary thing about Leonardo was his ability to *see.* His drawings are more accurate than other people's partly because he was better at seeing what was actually there rather than what he expected.
My favorite example of Leonardo's amazing eye concerns the trajectory of canon balls. In Leonardo's day the path of a canon ball was usually drawn like this, two straight line segments connected by a curve.
Leonardo realized that this was not so, that in fact a body in flight traces out the curve we call a parabola. Leonardo knew very little math -- he may not even have known the word parabola -- and anyway the first person to actually derive this curve mathematically was Galileo. But Leonardo could see it.
In fact Leonardo later went even farther than Galileo, because he realized -- again, just from seeing canon balls fly by -- that the actual trajectory was not a perfect parabola because it was distorted by air resistance, making the second half shorter. This was a calculation nobody could make until Newton's time, but Leonardo's eye was centuries ahead of the mathematicians.
Isaacson devotes two chapters to Leonardo's work in anatomy, and I found these sections fascinating. Working together with Marcantonio della Torre, a professor at the University of Padua, Leonardo carried out a long series of dissections of human corpses and prepared an amazing set of anatomical drawings. Their goal was to publish these results in the form of a large, expensive book that would set a new standard for anatomy. And they really might have done it, except that della Torre died of the plague and Leonardo ended up dropping the project, as he did so many others. It was left to Andreas Vesalius to publish the new learning that was being developed in Italy as a result of dissecting human bodies, in 1525. This was a loss, because Leonardo's drawings were better, and in a couple of crucial cases more accurate.
Which brings me to another thing about Leonardo, the foreshadowings of future science that people have gleaned from his notebooks. According to Isaacson, Leonardo wrote a detailed description of the aortic valve in the heart that correctly explained the mechanism that closes it between beats, a discovery that had to be remade in the 1960s. This one was new to me but there are others. The most famous is his statement that the air on top of a bird's wing is thinner than the air below it, and that this is part of what holds up birds in flight; now we call this Bernoulli's principle.
This again gets us back to those 7,000 pages of notebooks. It happens often in science that the person who gets the credit for the discovery is not the first one to have the insight, but the one who follows up in detail and publishes the results. A famous example is that Wilhelm Roentgen was not the first person to notice that something coming from radium clouded photographic film, he was the first one to follow up with a program of experiments on what we now call x-rays instead of just deciding to keep the film away from the radium. So if we had voluminous notebooks from thousands of other clever, scientifically inclined people, how many of their random jottings would look like science decades ahead of its time? On the other hand we do have thousands of pages of notes from Newton and they're mostly about the Bible.
Leonardo's notebooks are simply a riot of exploration and invention. They are full of machines, some practical and many more completely absurd. They explore the flight of birds, the movements of water, the expression of emotions on the face, the physics of falling bodies, the growth of plants, so many things that not even a 500-page biography can begin to discuss them all.
Leonardo is a fascination and a puzzle, a great painter, an even better draftsman, an extraordinary observer, a restless imagination, a procrastinator on an epic scale who started far more things than he finished. Walter Isaacson's book is a great place to begin getting to know him.