 In the process Grazulis traveled the country visiting dozens of libraries, museums, university archives, historical societies, and the like, to eventually chronicle 60,000 tornadoes, 50,000 of them included in a single 1,400 page book that is widely referenced.He is estimated to have read 25,000 microfilm reels of mostly major newspapers.His work concentrated in state libraries and the U.S. Library of Congress but also included local libraries when pertinent.