The Codex Leicester //top\\ May 2026

Leonardo wrote the Codex Leicester because he couldn't not know. He wasn't trying to publish a book; he was trying to talk to himself about the universe.

Leonardo was left-handed, and it’s believed he wrote this way to avoid smudging wet ink as his hand dragged across the page. To read it, you literally have to hold the page up to a mirror.

In 1994, the Microsoft founder paid for the manuscript at a Christie’s auction. That’s roughly $500,000 per page. At the time, it was the most expensive book ever sold. (Gates later had it scanned into a digital format for Windows 95 CD-ROMs—a perfect marriage of Renaissance curiosity and digital futurism). Water: The Star of the Show What did Leonardo obsess over in these 72 pages? Water. the codex leicester

And it just so happens to be one of the most expensive books on planet Earth. Despite the fancy name, this isn't a dusty medieval poem. It is a 72-page scientific notebook written entirely by Leonardo between 1506 and 1510. It is a firehose of genius, covering geology, astronomy, optics, hydrodynamics, and paleontology.

Why does water swirl down a drain? Why do mountains look blue in the distance? Why is the sky blue? Leonardo wrote the Codex Leicester because he couldn't

But there is another Leonardo. A Leonardo of obsessive curiosity, of messy reverse-script handwriting, and of questions so vast they stretched the limits of 16th-century science.

That Leonardo lives in the Codex Leicester . To read it, you literally have to hold

When we think of Leonardo da Vinci, we usually picture the Mona Lisa ’s enigmatic smile or the perfect proportions of the Vitruvian Man . We see the artist, the ultimate Renaissance man of beauty and grace.