One way Tolkien adds tension and time is to end with a cliffhanger for Sam and Frodo in book 4 (part 2 of Two Towers) you then start following Merry and Pippin in book 5 (part 1 of Return Of The King) and have to read all of that before returning to Frodo and Sam in book 6.
One way Tolkien adds tension and time is to end with a cliffhanger for Sam and Frodo in book 4 (part 2 of Two Towers) you then start following Merry and Pippin in book 5 (part 1 of Return Of The King) and have to read all of that before returning to Frodo and Sam in book 6.
Reference: A bit about the 6 books https://screenrant.com/lord-of-the-rings-tolkien-6-books-why/