In 1994, Bill Gates was about to become the richest person in the world. With all those billions burning a hole in his pocket, Gates decided to splurge on Leonardo da Vinci’s “Codex Leicester” for $30.8 million. That’s a lot of money for an ancient notebook – but this isn’t just any ancient notebook.

The 72-page document was written between 1506 and 1510 and contains a collection of scientific writings on astronomy; the properties of water, rocks, and fossils; air, and celestial light. Among these writings is speculation that the pale glow on the dark side of the crescent moon is caused by sunlight reflected from the Earth. So, technically, Leonardo described the phenomenon of planet shine a hundred years before astronomer Johannes Kepler proved it.

What the book didn't contain was the key to making Windows Vista good.