I started reading my (French version) of the newly released book Figopedia from JeremieBT ! It’s just excellent if you want to have a great theory/practice balance on how to work with light on your miniatures. Initially funded through an Indiegogo campaign you can find it now in online & brick and mortar stores for a reasonable price (between 35-45€).
The book is also available in English, you’ll find some sample pages & videos showing the book content on the publisher’s website. Go over at Figone.fr .