Would "This is a book about scientific methods" also be correct?
"this book is about the scientific method"?
It's subtly different.
Ini buku = THIS is a BOOK (that is about ...)
Buku ini = THIS BOOK (is about...)
It seems there are a lot of problems about the usage of "a" and "the" in English translation...!
Another option: "This is THE book about A scientific method".