More than 20 million documents related to the tobacco industry's scientific research, manufacturing, marketing, advertising and sales of cigarettes have entered the public domain thanks to lawsuits against tobacco companies. Now the Legacy National Tobacco Documents Library has made those documents easily searchable online. (Tobacco companies were ordered to put the documents online themselves, but their websites tend to be confusing and full of programming bugs.) If you want to know about the sleazy pro-tobacco activities of PR firms like Burson-Marsteller, APCO, Hill & Knowlton, Edelman or Mongoven, Biscoe & Duchin, the Legacy library is a great place to start your search.