before 1931;that deals about the protocol and directives of the palaces is?

The book that deals with the protocol and directives of palaces before 1931 is likely "The Court and Social Life in the Time of Queen Victoria: Being an Authentic and Comprehensive Account of the Court of the Greatest of Queens" by Grace Greenwood. This book provides insights into the etiquette, protocol, and social customs of the royal court during Queen Victoria's reign.

Imperial Household Law (1889)