In a giant 600 page book, there are a lot of details that can be forgotten (especially with size 8 font). Everyone can recall the beginning of the book by reading the first chapter, but the ending of a book is just as important as the beginning. The ending is a last impression that is left on the reader.
If the ending is good, the reader will enjoy the book and recommend it to friends because they will only be able to remember that great ending. The ending of a book can decide whether it is the next best seller or the next unknown.
Don’t forget to end what you write with a really good closing sentence or closing chapter because it is the ending that the reader remembers the most.