Lewis Anthony Dexter (1915-1995) pioneered the use of specialized interviewing as a tool in the social sciences. He argued that interviewing persons who have specialised information about, or who have involvement with, any social or political processes is different from standardised interviewing. In 'elite' interviewing the investigator must be willing to let the interviewee teach him what the problem, the question, or the situation is. He demonstrated that interviewing was a useful tool, but he also argued that it was not always the most appropriate method for revealing the information required.
In Elite and Specialized Interviewing decades of his practical experience, of both how to interview and how to use interviews, was distilled into a readable, yet rigorously analytical, book. First published in 1969, it remains as good a guide to the subject as the 21st century researcher can find.