 The first book (which was two volumes), results from the NRC funded work, was "Significant Tornadoes, 1880-1989".Sales of the book filled a gap in tornado information and strong sales led to an expansion, "Significant Tornadoes, 1680-1991".In turn, sales of this book and of Tornado Project videos and posters were robust enough that an update was published for the years 1992–1995.