 For example, his much imitated "Gazetteer of British Ghosts" (1971) and "Haunted London" (1973) - previously unheard of comprehensive and well-researched surveys (or geographical dictionaries - gazetteers) - which, through their encyclopaedic thoroughness, imparted authority to Underwood as an author on the subject he devoted his life to - ghost hunting.They also encouraged others to use them as resources to use to visit the sites he investigated for themselves.Underwood came to be known as a 'veteran psychical researcher ... representing the middle-ground between scepticism and uncritical belief'; the 'Sherlock Holmes of psychical research' - as Dame Jean Conan Doyle would say (when introducing him).