I am looking for books on enamelling of gold silver & copper.
As an enameller and teacher, I thoroughly recommend Ruth Ball’s
"Enamelling" (Jewellery Handbooks) published by A&C Black.
It’s clear, covers a vast range of topics and is very good at
beginners’ and more advanced projects.
Also highly recommended, by Linda Darty, "The Art of Enameling"
Beautiful and instructive.
Both available from Amazon.