Living halfway round the world I have found it quite hard to locate useful books/recordings but over the years we have accumulated some.
Yes, we have C. Sharp and Baring Gould, yes, we have the Penguin one and Bert Lloyd's one and also the books and recordings from the Coppers.
But one that I found interesting (and full of photos) is Bob Pegg's 'Folk', A portrait of English Traditional music, musicians and customs.
It's dated 1976 so I don't know where you'd find a copy today - no doubt C# House.
It's a bit like an essay but quite readable. My copy has pencil marks and underlinings throughout where I thought something was important and also a few places where I didn't agree!
For example, here's one that I've marked:
"In the end we find ourselves looking not at the true nature of something called folk song, but at the prejudices, both conscious and unwitting , of the folk song collectors."
But I think it gives a good overview of the collectors, the singers, the songs and the musicians.
Robyn