I.B. Cohen regards Freud's Interpretation of Dreams as a revolutionary work of science, the last such work to be published in book form.[174] In contrast Allan Hobson believes that Freud, by rhetorically discrediting 19th century investigators of dreams such as Alfred Maury and the Marquis de Hervey de Saint-Denis at a time when study of the physiology of the brain was only beginning, interrupted the development of scientific dream theory for half a century.[175] The dream researcher G. William Domhoff has disputed claims of Freudian dream theory being validated.[176]