Majesty: A Guide to Living with Royalty is a comprehensive guide to understanding the customs and etiquette of living with royalty. It covers topics such as how to address royalty, protocol for hosting royalty, and the proper way to interact with royalty.
From Wikipedia
Majesty is used as a manner of address by many monarchs, usually kings or queens. Where used, the style outranks the style of (Imperial/Royal) Highness, but is inferior to the style of Imperial Majesty. It has cognates in many other languages, especially of Europe.