The best interviewer of extended conversations on non-fiction books and writing in Australia is Richard Fidler: http://www.abc.net.au/radio/programs/conversations/
His interviews are thoroughly researched, the questions highly relevant and sequential and the discussion lively, intelligent and usually immensely entertaining.
Three of his best recent interviews include:
(1) How Hitler used heroin and meth to fuel the Third Reich. Fidler talks to Norman Ohler about his book Blitzed:
(2) Operating on the brink: the truth about brain surgery. Fidler talks to the neurosurgeon Henry Marsh:
(3) The bond between two alpine climbers which nearly killed them. Fidler talks to businessman Simon McCartney about an earlier life climbing vertical rock/ice faces:
Best from pre-2017 interviews, include:
Check them out!