Satoshi Nakamoto authored "Bitcoin: A Peer-to-Peer Electronic Cash System", a paper commonly referred to as the Bitcoin whitepaper. The whitepaper details the principles behind the Bitcoin proposal and the concept of the Bitcoin blockchain.
It is still a mystery who Satoshi actually is. It's not known whether Satoshi was a group of people or a single person that came up with the genius idea of the Bitcoin blockchain.
For more information about who created Bitcoin, take a look at our academy article.