Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff, It's me Christian Seger. Sometimes I like to imagine that long after I'm dead, a wealthy philanthropist is going to buy my diary for millions of dollars and lend it to museums across the planet. Then everyone would finally know the answer to today's question, what is the most expensive book in the world? Something by William Shakespeare, the Necronomicon, Twilight New Moon. Well, it all depends on if the
book is printed or if it's handwritten. If we're talking books that have had multiple copies printed, then the answer is the Bay Psalm Book, which sold for more than fourteen million dollars in November. It was originally printed by Puritans in Cambridge, Massachusetts, in sixteen forty. Seeking religious freedom, these settlers wanted their own translation of the Old Testament. Today, there are only eleven copies remaining, and it is considered
the first book printed in America. But if we include one of a kind handwritten texts, then the base Som book isn't even worth half the value of the most expensive book ever sold. That title goes to Leonardo da Vinci's Codex Lester, which sold for thirty point eight million dollars in nine to a little known computer programmer by the name of Bill Gates. Adjust that amount for inflation, and today the Codex is almost worth fifty million dollars.
In fact, that's forty million, five thousand, five hundred and sixty one dollar and forty cents if you want to be technical. It's an unbound, seventy two page notebook filled with da Vinci's drawings and thoughts, mainly about how to move water. Yeah, the most expensive book in the world is basically a plumbing manual. More on that in a minute.
A lot of da Vinci's writing was lost to history, almost half of it, in fact, So the Codex Lester is mainly important because it's a single collection of his focused ideas. The Codex is written, like many of da Vinci's works, in something called mirror hand. All the letters are reversed and it's written from right to left, so the only way you can read it is when it's held up to a mirror, and you probably need a fluency and antiquated Italian as well. So it's a book
about water that's written backwards. Well, to be fair, that's oversimplifying things a bit. It's primarily about how astronomy and geology relate to water, considering the functionality of tides, eddies, and dams. Really, da Vinci was trying to figure out how to harness the power of moving water. He demonstrates how pressure increases with depth in a fluid, and the
Codex examines configurations of siphons and differently shaped pipes. He's particularly interested in the fluid mechanics of how water moves around obstacles. This manuscript was first purchased in seventeen seventeen by a guy named Thomas Coke, who later became the Earl of Leicester, hence the title Codex Lester. But in night an art collector named armand Hammer bought it, changing
its name to the more badass Codex Hammer. This only lasted fourteen years, though, until Gates bought it and changed it back. Then he made it into a screensaver for windows. Actually, Gates seems genuinely inspired by da Vinci's example of pushing himself to find more knowledge. He's even loaned the book to a number of museums over the years so it can be viewed and studied by the public. So that's the most expensive book in the world for now, until
the Codex Sager hits the Southebys auction block. Check out the brainstuff channel on YouTube, and for more on this and thousands of other topics, visit how stuff works dot com.