This entire site is about Open Source Intelligence (OSINT) and more recently, its two applications in the public interest now that “OSINT” has been captured and buried by governments–anyone dumb enough to “classify” OSINT has no clue.
The two new applications are Public Intelligence in the Public Interest (PI2) and, originally a Swedish military peace intelligence concept articulated by Col Jan-Inge Svensson, Land Forces (Ret) and others, M4IS2 (Multinational Multiagency Multidisciplinary Multidomain Information-Sharing and Sense-Making).
The Handbooks and the Historic Contributions are “best of OSINT” in practical terms. The References and History of Opposition contain a lot of information about the inherent conflict between secret bureaucracies and the real world. The original one-page of links, BASIC, and the original LIBRARY table of all contributions within OSS.Net, remain useful.
The two core references in the literature remain: