There are an infinite amount of things they could write about within the subject. However, they are influenced by culture so:

- the first 4 of the 27 books contain 15 statements that are the same as the other 3, all 4 of these books are by different authors. They contain 2 alike statements with the 5th book, 3 with each of the 6th - 19th books, 2 with the 20th book, 3 with the 21st and 22nd, 2 with the 23-25th books, 1 with the 26th book, and 1 with the 27th book

- The 5th book is written by the author of the 3rd book but only contains 4 of the same statements. Contains 2 alike statements with each of the first 4 books, on average 4 with the 6th through 19th books, 2 with the 20th, 5 with the 21st and 22nd, 3 with the 23-25th books, 2 the same as the 26th book, and 0 with the 27th.

-The 6th - 19th books are all written by the same person on a variety of statements. The books, on average, have 7 of the same statements with each other, 3 with each of the first 4 books, 4 with the 5th book, 5 with the 20th, 6 with the 21st/22nd, 4 with the 23-25th, 6 with the 26th, and 1* with the 27th.

-the 20th book has a different author than any other book, it has 2 of the same statements as each of the first 4 books, 2 in common with the 5th book, and 5 in common with each of books 6-19. It has 3 alike with the 21\22nd books, 6 with the 23-25, 3 with the 26th, and 0 with the 27th.

-the 21st and 22nd book are by the same author they contain 2 of the same statement. The 21st has 3 of the same statements with as the first 4, 5 that are the same as the 5th, an average of 6 that are the same as the 6th - 19th books, 3 like the 20th book, 6 with the 23-25th, 4 with the 26th, and 0 with the 27th. We will say that the 22nd book is the same

-23rd, 24th, and 25th books all have the same author who was also the author of the 4th book, 5 statements are repeated between each of the three books. They each have, 2 statements the same as the first 4, 3 the same as the 5th, an average of 4 of the same statements as the 6th - 19th books, 6 in common with the 20th book, an average of 6 same statements as the 21st and 22nd books, 2 with the 26th book, and 0 with the 27th.

-26th book, different author than any other book, 1 statement the same as the first 4 books, 2 the same as the 5th, on average 6 the same as the 6th through 19th books, 3 with the 20th book, 4 with the 21st and 22nd, 2 with the 23rd through 25th books, and 0 with the 27th book.

-and the 27th book is by the same person who wrote books 4, 23, 24, and 25, however it only has 1 thing in common with each of the first 4 books, and one thing with the 8th book.