OSINT

Robert Steele: Open Source Intelligence 101 (Intelligence Tradecraft in the Third Millennium)

Intelligence is the art and science of evidence-based decision-support. Intelligence is not defined by its inputs (spies, secrecy, money, risk) but rather by its outputs – tailored actionable decision-support. In this context, the fastest, least expensive, and very often the best intelligence is achievable using mostly – and sometime only – open sources and methods.