Aman Trivedi
The world's most expensive book was written in the 15th century and was written by Leonardo da Vinci.
The name of this expensive book is 'Codex Leicester' and the book is written in Italian with 72 pages and 18 sheets in it.
This book is the most famous scientific journal of Leonardo da Vinci.
This book was first bought by Thomas Cook in 1717.
Bill Gates bought this book in 1994. At that time, he paid 3.08 crore dollars for this book.
Its value in today's Indian rupees is more than Rs 250 crore.
Vinci has included his explanations in this book, like why fossils are found in the mountains, the flow of water in rivers or the moon's brightness, etc.