Lighting Labs Releases Lightning mainnet Server lnd 0.4-beta. While focused on developers this is the first release that runs on mainnet that uses real bitcoin.
ACINQ released version 0.2-alpha of the Eclair Lightning Network server.
The original Lightning Network 2015 Whitepaper. “Creating a network of micropayment channels enables bitcoin scalability, micropayments down to the satoshi [1/100m Bitcoin], and near-instant transactions.”
UPDATE: The link is to the Jan 14, 2016 version.
The original 2009 white paper by Satoshi Nakamoto that launched Bitcoin. The most important line in the entire white paper is: “The network is robust in its unstructured simplicity. “