Ralph Henry Johnson (born 1940) is a Canadian American philosopher, born in Detroit, Michigan. Johnson has been credited as one of the founding members of the informal logic movement in North America, along with J. Anthony Blair who co-published one of the movement's most influential texts, Logical Self-Defense, with Johnson. Alongside its founder, Blair, Johnson co-directed the Centre for Research in Reasoning, Argumentation, and Rhetoric at the University of Windsor. As Johnson and Blair write in the preface to the newest edition of Logical Self-Defense on the influential nature of the text: "We might note that the theoretical perspective introduced in Logical Self-Defense has proved quite influential among textbook authors. It is to be found in modified form in A Practical Study of Argument by Trudy Govier, in Attacking Faulty Reasoning by T. Edward Damer, in Logic in Everyday Life and Open Minds and Everyday Reasoning by Zachary Seech, in Thinking Logically by James B. Freeman, and in Good Reasoning Matters by Leo Groarke and Christopher W. Tindale." Source: Wikipedia (en)