Bookworms often have a rare jewel in their collection that they are unable to throw out — despite efforts to こんまり (Konmari, tidy in the method of Marie Kondo by getting rid of clutter) around the house. For me, this book is the 1965 エチケット事典 (Echiketto Jiten, Etiquette Dictionary).
I found my copy after the Japanese consulate in Chicago partook in some Konmari of their own. I was unable to resist its yellowed pages, the cameo pendants that decorate its cover, and the tagline across the top that provided a hint as to the contents inside: 交際・慶弔・服装・手紙 (Kōsai/Keichō/Fukusō/ Tegami, Relationships/Congratulations and condolences/Clothing/Letters).
The 366-page publication was included as an appendix for the April 1965 issue of the magazine 婦人生活 (Fujin Seikatsu, Women's Life), and its goal is to help guide the Japanese through the terror that is modern life; every instance of 交際 (kōsai), which means "relationship" but can also be thought of as "social interaction," represents the possibility of unthinkable embarrassment due to etiquette failure.