PT author of The Doctor's Communication handboook b.1946, is a retired general practitioner and novelist.
PT author of Flights of Fancy: Birds.... b.1926, was a naturalist.
PT author of Greencomber b.1940, was a writer of science fiction.
The www.fantasticfiction site list does not agree with this allocation but, I believe, is incorrect. Owners of the books who know better please adjust!