Prediction markets are widely considered the best forecasting tool. Augur is an open, global platform where anyone anywhere can create, monitor or trade in prediction markets about any topic. Think of it as an "Early Warning System'' with the most accurate event forecasts, a potential "Google Search", "Bloomberg Terminal" or "Reuters Terminal" for crowdsourced event forecasts. The system plans to use the "Wisdom of Crowds'' ("collective intelligence'') via market incentives, "Long Tail'' dynamics and blockchain technology to securely generate a more accurate, robust and unfiltered array of dynamic event forecasts than any alternative can match. Augur is decentralized, self-regulating, pseudonymous and autonomous. It offers the promise of markets without exposure to counterparty risk, principal-agent problems or central points of control, failure or censorship. No person is ever in direct control of someone else’s funds or in a position to single-handedly threaten the system’s integrity. The software is comprised of smart contracts perpetually deployed on a blockchain network, which enables applications deployed to be immune to local outages while benefiting from the entire community's security. All interactions with markets are communicated as database transactions between unique accounts powered by immutable software instructions.