Alright mate, only ferreting book I have ever bought is called 'Ferreting for the future' by Simon Whitehead. I give it 10/10, and would recomend it to anyone. Before I read the book I didnt have a clue about ferrets and ferreting, its by no way an instant expert and like the others have already suggested, its best too get out in the field but its a good starting point
It covers EVERYTHING, from what too look for when getting a ferret, its housing (Hutches, runs and how too clean them propperly), loads about handling them, teaching them not too bite, checking for ailments, all the differ