Complex sentence: No author is known; the book is most likely a collection of pieces from various sources put together by an anonymous editor and used by Okinawan-based quanfa practitioners during the 19th and early 20th centuries.
Split into simpler sentences: No author is known; the book is most likely a collection of pieces from various sources put together by an anonymous editor. It was popular in Okinawa among Okinawan-based quanfa practitioners during the 19th and early 20th centuries.