Leonardo da Vinci is an intimate examination of one of history’s greatest minds. Walter Isaacson’s sincere, humanizing account provides fuller context to Leonardo’s life: his humble origins, his growth as an artist and engineer, and the stories behind his masterpieces. Isaacson goes on to argue that more than simply admiring Leonardo’s qualities, we should strive to learn and emulate them. 

Piero da Vinci, was a wealthy dignitary who began seeing Caterina Lippi, an orphan and a peasant. He was twenty-four; she was sixteen. Given the vast social and economic gulfs between them, a formal union was out of the question. Piero married another girl before Leonardo was even born, but also saw to Caterina’s marriage, and made sure that she and his bastard Leonardo were cared for.

Leonardo da Vinci was born in 1452, within a few years of Christopher Columbus and Amerigo Vespucci. Had he been a legitimate son, a standard, Church-approved production, he would have been locked into his family occupation and become a notary just like his father—and his great-great grandfather. This would ultimately be to Leonardo’s benefit—and to posterity’s.

In terms of historical-cultural circumstances, there was no better time to be born a bastard than during the Renaissance in Italy. One historian goes so far as to label this era “The Golden Age for Bastards.” Several popes alive during that time wrote of the prevalence of illegitimate children without an air of condemnation, and it is believed that Popes Pius II and Alexander VI—both alive during Leonardo’s lifetime—were fathers to several illegitimate children.  

There was a good turnout for Leonardo’s baptism because illegitimacy did not carry the stigma that it so often has throughout human history. Especially among the Italian aristocracy, there was no sense of shame about such matters. Without these particular social and cultural conventions, the chances of Leonardo achieving the same level of success would have been far slimmer.

His status as an illegitimate child did complicate legal matters of inheritance. Existentially speaking, too, it was tough only “sort of” belonging to a family. The sense of belonging was never a full one, which could explain Leo’s obsessive search for patrons who would support him unconditionally. This familial gray area led to bastards adopting unconventional lifestyles, and it is possible that this state of liminality shaped Leonardo’s knack for seeing things that others missed.

Another blessing in disguise was his exclusion from Latin schools, where students were taught history, ancient literature, and inculcated with traditional inherited wisdom. This forced him to take education into his own hands, learning through trial and error and a few years in a trade school. Leonardo had strong opinions about the students who came out Latin schools. In one scathing journal entry, he wrote, “They strut about puffed up and pompous, decked out and adorned not with their own labors, but by those of others.”

Florence in the 1400s was a booming center, where business, technology, and art became an interconnected trifecta of creative enterprise. It was also a hub for intellectual discussions. It had the highest literacy rate in Europe at that time. Humanists and literati were right at home there, bursting with optimism about human potential to achieve great things.

Leonardo’s father showed a guild master named Verrocchio some of Leonardo’s drawings and sketches, and, apparently, Verrocchio was duly impressed with the fourteen-year-old , impressed enough to take him on as an apprentice. Leonardo thrived in the bottega, or workshop, where Verrocchio trained and employed artisans and craftsmen. The master’s influence over his pupil is quite apparent.

For example, in Verrocchio’s work, we see an attention to human anatomy and how the body’s movement activates particular tendons and sinews. His dedication and ability to portray accurately human form in motion is a skill that his young apprentice would  adopt and then perfect.

In abacus school (i.e., trade school), math was a means to the end of excelling in commerce, but Verrocchio instilled in Leo a love of math for its own sake, showing him the beauty inherent in geometry and its myriad expressions in nature. Leonardo would later refer to this harmony in the natural world as “nature’s brushstrokes.”

Leonardo learned sculpting, painting and mastered the skills of rendering perspective, light and shadow, and sfumato, or the blurring of lines in a piece for added subtlety and intrigue. 

Verracchio’s guild was also responsible for putting on pageants and theatrical performances. Leonardo loved every aspect of theatrical production. It never became more than a hobby, but he showed himself to be a brilliant actor, prop designer, and a master of special effects—one of many realms in which he integrated  art and engineering. What is more, many of the fantastical contraptions Leonardo sketched—sketches that would go on to inspire such inventions as armored tanks and planes—were first conceived of here as potential theater props.

When Leonardo was twenty years old, his training in Verrocchio’s bottega, or guild, was over, but Leonardo continued living there. So collegial and friendly was the atmosphere among the artisans and craftsmen there that he did not want to leave.

Leonardo was often described as a man of exceptional beauty and grace. He enjoyed donning flamboyant outfits dissonant with the cultural trends of his day. By all accounts, he was well-liked and opened his home to fellow artists, rich or poor. As he gained wealth and reputation, he owned horses, and apparently loved animals. Early biographer and artist Vasari mentions that Leonardo would often buy caged doves at the market for the sole purpose of liberating them.

His love of animals led him to embrace vegetarianism. It was a decision made on ethical grounds. He believed that, unlike plants, animals were capable of movement and experiencing pain, which, for Leonardo, made harming them immoral.

Leonardo was also openly gay, and found no shame in his sexual engagements or open conversations about the phallus. He was not alone in his preferences. The city of Florence had a growing reputation for drawing people with homosexual inclinations, so much so that a common German term for gays was Florenzer.

Platonic cults were becoming popular at that time, and Leonardo appears to have been caught up in the zeitgeist, likely engaging in relations with boys as well as men. One boy, Salai, was ten years old when he came to live with Leonardo, who was thirty-eight at the time. Salai literally means “little devil.” It was a playful nickname that Leonardo gave him soon after meeting him. Salai was Leonardo’s companion the rest of Leonardo’s life. The exact nature of their relationship is an enigma, but there’s good reason to suspect that it became intimate.

Perhaps it was because of his exposure to notaries that Leonardo developed a love of recording his thoughts in notebooks. Around the time he moved to Milan in the 1480s, he began the practice that he would continue for the rest of his life. He was always writing down to-dos, jotting down reflections and observations, drawing sketches of plants, people, and landscapes. He carried his notebook everywhere; it hung from his belt. The practice was actually becoming quite common in Florence at that time. People would have referred to a notebook like Leonardo’s as a zibaldone. Interestingly, his written reflections were very rarely introspective—they were rather his account of the marvelous world around him, replete with beauty, mystery, and humor.

He had a wild imagination that bordered on fantasy and a curiosity that was absolutely insatiable. Sometimes the mental meanderings are hard to follow from the notebook. A single page could easily contain various right triangles as he tried to map the transformation of shape, new mechanical conceptions, the profile of an elderly man, and the wings of a dragonfly. Paper was hard to come by in that time, so no space was wasted. Another interesting feature of his notes is that they rarely contained dates, which made organizing his work chronologically a formidable task.

The contents of the earliest notebooks pertain mostly to engineering and art, but his repertoire expanded with time. His to-dos were especially strange, sometimes humorously so. Here are a handful of entries:

Sketch Milan.

Describe the tongue of the woodpecker.

Go every Saturday to the hot bath where you will see naked men.

Inflate the lungs of a pig and observe whether they increase in width and in length or only in width.

Some scholars estimate that the 7,200 pages of Leonardo’s notebooks that have been discovered comprise only a quarter of the notes that Leonardo took. The vast array of information, drawings, observations, and questions to be investigated is bewildering. It’s difficult to trace the interconnections that Leo intuited, but somewhere in his mind was a sense of unifying harmony in all things—ways in which art, math, and science all came together.

The Vitruvian Man is that iconic sketch of a nude figure with arms outstretched and legs drawn both together and splayed. The sketch was inspired by a first-century BC Roman architect and military leader, Marcus Vitruvius Pollio. As in Renaissance Italy, many in Ancient Rome were fond of the idea that man was a microcosm of the world or universe. In his writing, Vitruvius had spelled out what he believed to be the true proportions of a man’s body. He went on to posit that, given the interconnections of man’s form and the world around him, a temple’s architecture should mirror features of human form. Leonardo himself was taken with the same cosmological principle, and had explored the perfect dimensions of the human body through observations of both people and corpses.

Some of Leonardo’s friends attempted sketches of the Vitruvian man based on the proportions that the ancient had described (his foot should be one-sixth of his height, his forearm one-quarter his height, and so on), but none compared with Leonardo’s. The lines Leonardo drew were crisp and confident, not hazy and timid outlines as his friends’ attempts had been. And instead of a simple sketch, Leonardo’s Vitruvian Man was a detailed artistic statement, with shading and muscle contours that are both beautiful and anatomically accurate.

Leo would have been thirty-eight when he drew this, and some suspect the Vitruvian Man to be a self-portrait. Based on Leonardo’s notes, the maxim that “Every painter paints himself” is one that Leonardo seemed to accept. Whether this was Leonardo or archetypal man, Leonardo shows us man as a world in his own right, and locates him within the macrocosms of earth and universe: man within a perfect square within a perfect circle.

It turns out that the woman who posed for Mona Lisa was not a central figure in the Florentine aristocracy. It was only after recently attaining some success in the silk trade that Lisa’s husband commissioned Leonardo to paint his wife, Lisa del Giocondo. Historians are not sure why Leonardo, by then a celebrated engineer and artist, agreed to the commission. There were far more lucrative offers from other patrons, he had been focusing on engineering far more than art at that time of his life, and it would have meant leaving Milan. The author believes that it was Lisa’s relative obscurity that drew Leonardo. It would have given him the freedom to create a portrait he wanted without catering to the preferences of persnickety patrons.

It’s not just because of particular historic circumstances that Mona Lisa has become the world’s most famous painting. It’s because of Leonardo’s brilliantly executed artistic ability. Mona Lisa shows his ability to convey subtle emotion in a glance that arrests and engages the viewer. There’s a depth of personhood in Mona Lisa that calls up similar depths in the person on whom her eyes rest. This piece came toward the end of Leonardo’s life, and it displays his maturity as an artist, and a profound understanding of human nature and anatomy.

Early biographer Vasari remarked that Mona Lisa “was painted in a way to make every brave artist tremble and lose heart.”

The German philosopher Schopenhauer once remarked that, “Talent hits a target that no one else can hit. Genius hits a target no one else can see.” Leonardo was undeniably a genius. He was a true Renaissance man who surpassed all others with his sheer breadth of knowledge. Such labels, however, can give the impression of super human ability, which can obscure his humanity. He was a mere mortal like the rest of us. This is clear from the piles of half-finished paintings, sketches, and essays that Leo walked away from and never returned to.

His wild imagination bordered on fantasy and led to drawings of contraptions centuries ahead of his time, but oftentimes his ideas were never carried through to completion. Part of the reason for this was that to declare a work is “finished” is to freeze it in its state of imperfection. For Leonardo, there was always something to improve in a piece of art, another cue to be taken from nature that would render the piece yet more life-like. Leo was a genius, but the capricious, impulsive, distractible, curious aspects of his character make it easy for us to relate to him.

Were Leonardo our contemporary, it’s very likely he’d be diagnosed with ADD and saddled with a Adderol regimen.  We have reason to be thankful that he was not, as the scattered, manic scribblings, sketches, and heart-felt paintings—though at times foreboding—yielded ideas and art that continue to inspire half a millennium later.

Leonardo’s humanness makes him accessible to us. We no longer need to put him on a pedestal, but can view him as someone from whom we can learn. The quirks and habits that brought out the best in Leonardo can bring out the best in each of us as well. 

One lesson that can be readily distilled from Leonardo’s story is the importance of staying incurably curious and preserving a sense of wonder. If you have lost this, make children your teachers—they’re often the best at this. Another lesson would be to pursue truth for its own sake, not just because it is practically useful in the foreseeable future. 

Don’t be bound by specialization. Leonardo shows us what wonderful things merge when there’s crosspollination between art and science. More recently, Steve Jobs advocated a similar stance, contending that creativity comes at the nexus of technology and liberal arts. Leonardo also teaches us the value of thinking visually. Abstract thinking and developing mathematical formulas were never his strong points, but he saw and drew out the beauty in the patterns and variations that nature produces.

Leonardo also shows us the importance of making lists, taking notes, and writing on actual paper. Try making lists and writing on real paper. Notebooks are written records that our grandchildren will be glad to read some day. Handwritten accounts have a longevity, a beauty, and a mystique that social media posts will never capture. To see personal, handwritten reflections and drawings, with words scratched out and a preferred word substituted—it all creates an intimate window into the past. It will show quirks and personality that cannot be conveyed on a tablet or in a text message.