From the mid-1960s until his death in 1989, Willard Day wrote and spoke on two central themes: the distinctive characteristics of Skinner's scientific philosophy, and the implications of Skinner's work for the development of scientific methods relevant to verbal behavior. Only some of this work made its way to publication. Edited by Sam Leigland, this book brings together in one place the most important papers, published and unpublished, of the leader in behavioral philosophy.