Our Immigrant Ancestors was my first introduction to the wide world beyond Mexican and Chinese cooking. I hadn't heard of anyone else who used it, so thanks for the reminder (Though because I bought it when I was in my
thirties, I didn't appreciate the reminder about my age...

)
A really wonderful source for Asia, including south, east, southeast and the Indian subcontinent is The Complete Asian Cookbook by Charmaine Solomon.
One of my favorites just for reading and laughs is The Times Picayune Cookbook published in 1908, which I picked up in a used book store in New Orleans. It has all the classic creole and cajun recipes, but in those days the expectation is the cook actually goes out back to the pond and harvests the turtle, removes the shell, guts the critter and preps the meat. Instructions are provided!