Just about to mention that; in fact, I think of the old King Penguins as Folk Art in themselves, each one is a classic of its kind and I collectv them avidly. I think my favourite is the Misericords volume, but The Leaves of Southwell (text by Pevsner) runs it a close second (along with Garden Birds). Popular English Art returns us to the usage of Popular in lieu of Folk, which to me is less intersting. Child used Popular in this sense too, and the whole notion of Popular Art / Popular Music is richly fascinating in terms of Tradition.

Anyway, Popular English Art (the book) takes us from the Herefordshire School of Romanesque Sculpture through figure heads, samplers, fair ground horses, Gypsy vardos, pottery, gravestones*, ships in bottles, Punch & Judy and horse brasses, so quite a range. No slip ware though, of which I'm a great fan.

Also worth looking out for in King Penguin is The English Tradition in Design which begins with amazing carved oak chests from the 13th century and ends up with fabric from the Metropolitan Line trains circa 1947 when the book was published.

Again, try Abebooks.   

* Which reminds me - those Folkies of a Macabre cast of mind check this out: A Morbid Eccentric