Download the original whitepaper here. http://bitcoin.org/bitcoin.pdf
In November 2008, a paper was posted on the internet under the name Satoshi Nakamoto titled Bitcoin: A Peer-to-Peer Electronic Cash System. This paper detailed methods of using a peer-to-peer network to generate what was described as "a system for electronic transactions without relying on trust". In January 2009, the Bitcoin network came into existence with the release of the first open source Bitcoin client and the issuance of the first bitcoins, with Satoshi Nakamoto mining the first block of bitcoins ever (known as the "genesis block"), which had a reward of 50 bitcoins. The value of the first bitcoin transactions were negotiated by individuals on the bitcointalk forums with one notable transaction involving a 10,000 BTC pizza.
"Satoshi Nakamoto" is a pseudonym for the unknown person or people who designed the original Bitcoin protocol in 2008 and launched the network in 2009. Nakamoto was responsible for creating the majority of the official Bitcoin software and was active in making modifications and posting technical information on the BitcoinTalk Forum.