Strongly disagree! If used as described it has not been broken. Only if letters in the same sentence are reused (if your lazy) or you limit yourself to a single page (lazy again). The permutations are huge.
2,7,16,73,45,67,11,42,5,3,51,48,2,6,35,88 is "AAAA" encrypted. All you have to know is the book I used, which number is the page, which number is the sentence, and which is the character. (I didn't use paragraph I'm lazy it also is usually a smaller number and could be spotted.)I also changed the sequence somewhere in the string.
There are several pitfalls. A part of the book cannot be reused in other messages else the overlap allows unfolding of the code. It's not easy to select a book for two people to share and that is not obvious to the adversary; Bible, Quotations of Mao, Shakespeare, Book of Common Prayer, Gone With the Wind, Dictionary, etc., are all rather obvious. It's easy to check the code against many known books. Some books just do not have enough words (even The Dictionary) and using the book to select letters rather than words leaks even more information. The adversaries may also be suspicious that a suspected spy has a copy of a particular book.