What is everyone's absolute favorite book?

idk how many times this has actually been asked here, and forgive me if the answer is too many, but I am so curious I had to ask it.

my favorite I feel like is either one that everyone dislikes reading, or one that everyone loves: the last book in Omen of the Stars, The Last Hope. it's just SO exciting to me, and there's never a dull moment, which I love. also, OOTS contains a lot of my favorite characters, and it's just so amazing.

yes, Firestar dies, which is SUPER sad (his literally one of my fav characters), but it's the perfect level of drama for me - all of that about the fourth cat and the resolution

edit: actually surprised to see how many of y'all love Crookedstar's Promise. that was definitely my favorite for a while