Jackson added a lot of material from the Appendices of the LotR books. Tolkein had put a lot of the back story and connecting stories (relating the events of “The Hobbit” to the plot of “The Lord of the Rings”)into the appendix.
My son was telling me about the prologue. He was pretty excited since he had just read the Hobbit. He is just now getting to the first chapter.
I’ll mention the appendices to him. Thanks!