Debrett's Etiquette & Modern Manners
Etiquette & Modern Manners edited by Elise Burch Donald is a gem. I'll be honest, I read this book for shits and giggles. It's a hilarious read when you put the british accent on and read about something as niche as dealing with the bore.
Jokes aside, there were some genuinely interesting things. A lot of societal norms are taken for granted and the book explains the background for things like why there are small vs big forks/knives/spoons and the same for different types of drinking glasses or table clothes. I can't claim to actually have retained much of that though -- it's probably more sticky to play around with them and actually use it.
Within the labyrinths of the book also rest 25 pages of "Correct Forms of Address," for everyone from a duchess, a dowager duchess, or a Lord Privy Seal.
Here's some other pages:
