The Bitcoin white paper, titled "Bitcoin: A Peer-to-Peer Electronic Cash System," was written by an anonymous person or group of people under the pseudonym Satoshi Nakamoto. It was first published on October 31, 2008. The paper outlines the concept of a decentralized digital currency, Bitcoin, and the underlying technology that enables it, known as blockchain.

The white paper introduces several key concepts:

1. Peer-to-Peer Network: Bitcoin operates on a decentralized, peer-to-peer network that allows users to send and receive payments directly without the need for a trusted third party (such as a bank).

2. Decentralization: Bitcoin relies on a decentralized ledger (the blockchain) maintained by a network of nodes that verify transactions, ensuring security and trust without a central authority.

3. Proof of Work (PoW): The white paper introduces the idea of a proof-of-work mechanism to validate transactions and secure the network. This process requires participants (miners) to solve complex mathematical problems, consuming computational power to add blocks to the blockchain.

4. Digital Signatures: Bitcoin uses cryptographic signatures to ensure that only the owner of the funds can authorize transactions.

5. Fixed Supply: The total supply of Bitcoin is capped at 21 million coins, ensuring scarcity and combating inflation.

6. Double-Spending Problem: The white paper addresses the problem of double-spending, which could occur in digital currencies, by using the blockchain to keep a public record of all transactions.

The Bitcoin white paper is widely regarded as the foundational document for the cryptocurrency movement and remains the basis for Bitcoin's design and development.

You can read the full paper here.