Who is the author or authors of Harcourt math book third grade? California edition?

There is no way to tell. Almost every K-12 textbook has anywhere from 2 to 8 authors listed on the title page. 95% of the time, not a single one of them has contributed a single word to the book. It's all a scam. The books are written by back-room hacks and the authors are paid for the use of their names. One lady named Anthea Maton was listed as author of more than 250 textbooks in all sorts of fields. On TV (maybe 60 Minutes) she was handed a book with her name on it and asked if she'd ever seen it. She said no.