The number is not specific.
Please list the "at least three books" you think exist.
Please be specific.
And I saw the dead, small and great, stand before God; and the books were opened: and another book was opened, which is the book of life: and the dead were judged out of those things which were written in the books, according to their works.
Since there were "books" and "another book"...., that means there were at least 3 books.....It could have been more....
One of the books was called the book of life. The others, I wouldn't speculate on....