Propaganda—the art and science of mass persuasion—is, by definition, the most important factor that shapes public opinion. And yet its patently transparent mechanisms and obviously visible results are studiously ignored in this distractedly entertained society. Although propaganda may not be bad per se, historically it has negative associations, owing to its chronically dishonest use by leaders of all stripes to sway an otherwise reluctant and malleable population to support war and then later to justify it. It’s also legitimately (or not) used to persuade people to identify with a political, social or religious point of view. Its most popular use, of course, is simply to sell product. Disinfopedia.org is an ambitious Web site that attempts to publish the definitive “playbook” of propaganda techniques to which we are all unwitting victims. Its “open content” structure allows users around the world to contribute definitions and examples or to edit existing sections. This free, comprehensive and publicly-authored encyclopedia is an indispensable tool for identifying and correcting the disinformation that distorts democracy.