I think the statistic was that at one period of time his books were the most stolen from british public libraries I have one of the misprinted "Modern Ferretting" originals,only a small number were churned out before someone proof-read and spotted the spelling mistake.Like him or loathe him he certainly carved a niche for himself and has anyone since been more prolific?
The Jack Russell Terrier (1976).
Rogues & Running Dogs (1976).
Modern Ferreting (1978).
Tales of a Rat Hunting Man (1978).
The Working Terrier (1978).
The Complete Lurcher (1979).
Adventures of an Artisan