Look inside the rare Leonardo da Vinci notebook that Bill Gates paid more than $30 million for

Microsoft cofounder Bill Gates is known to be an avid reader, and his home library is filled with rare books selected by a professional book dealer.

In 1994, he purchased Leonardo da Vinci's "Codex Leicester," a manuscript that dates back to the 16th century. He paid $30.8 million for the journal at auction, a price that made it the most expensive book ever sold.

Gates has put the notebook out on loan to select museums this summer. Currently on view at the Minneapolis Institute of Arts, the Codex Leicester will travel to the North Carolina Museum of Art in Raleigh on August 30.

Before Minneapolis, the manuscript was on exhibit at the Phoenix Art Museum.

Written between the years of 1506 and 1510, the 72-page notebook provides a rare glimpse inside da Vinci's mind, complete with sketches, diagrams, and early iterations of ideas.

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The Codex Leicester is just one of 30 scientific journals Da Vinci is believed to have authored, but many consider it the most important.

The text is written in Da Vinci's famous mirror-image style, meaning that the words are supposed to be read from right to left. The words are written in an antiquated version of Italian, which is translated on touchscreens situated around the exhibit.

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The Codex Leicester primarily focuses on Da Vinci's thoughts relating to water - tides, eddies and dams - and the relationship between the moon, the Earth, and the sun.

"It's not a simple document that records his thought processes; it is a very messy document in which he develops his ideas," show curator Alex Bortolot told the Star Tribune.

It makes sense that a journal focused on brainstorming ideas would appeal to an entrepreneurial-minded person like Gates.

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According to the Star Tribune, Gates has asked that visitors to the museum go through a security screening similar to what you would find at an airport.

He usually makes the manuscript available for exhibit once a year.