Two Interesting Books (Hanyu Pinyin in 1929?)

Just going through some old books. Well one (Chinese Synonyms Usage Dictionary, Crane, 1994) isn’t that old, but very useful - one of the few books designed for English learners of Chinese), but the other…

Wenli Particles, by J.J. Brandt, pub. The North China Language School, Peiping, 1929, has what it calls a “New Latin Concordance to Wade-Giles Romanisation” in the back, giving a comparison of what is Hanyu Pinyin to Wade-Giles.

HYPY in 1929 ? It’s called “New Latin” in here, but it’s definitely HYPY. Does anyone have the low-down on the invention and development of HYPY, or know any books on the subject ? When I was at uni we were told it was developed in the 40s by some Eastern Bloc professor, and picked up by the CCP later on. But this book is a first edition from 1929.

I’m confused.