This book by Marilyn Karmason, published in 1989, remains the 'bible' on collecting majolica. It is out of print, sadly, but is still widely available in used condition. I treasure my copy! It is filled with in-depth history about each of the world's majolica makers and traces the rich history of this incredible form of pottery with plenty of visual reference. Gonna get this book even though it's out of print.