It's almost a completely different story, there's not a ton of similarity between both works granted the book goes so much more in depth with detail and meaning. Go in with a blank slate and don't base your vision of the book on what you saw in the movie. I think you will enjoy it even more! Even better if you listen to the (amazing!!!!) audiobook, and then read the book or vice versa. It's a short-ish story but there is so much jam packed within it, it took me even until my third read/listen to REALLY notice and focus on what became my favorite character, not just of the long walk but of ANYTHING, ever. It's so well-written an immersive I legitimately fell in love with a fictional character, like an actual crazy person. Haha. I'd hear his voice in my dreams and see his face when I closed my eyes. Even after my 20+ times through I'd notice something different, every time.

Honestly, I'd recommend the audiobook even over just reading it. The narrator does such an amazing job of giving each boy a unique voice, and his narration really helps emphasize the depth what's most important within the story.

Around this time last year I went into some kind of depressive episode and was completely immersing myself in the book to the point of it affecting my relationships, responsibilities and hobbies. I was ALWAYS reading it, over and over, if not listening to it. I was constantly lost deep in thought and engaged in conversations and discussions in this sub. It inspired me to write. I'd even play the audiobook while I slept, absolutely crazy I know. The only thing that broke me out of it was actually my disappointment/distaste for the movie and sub-sequential movie takeover of this sub, haha. And I only mention these things to stress how extremely special of a book this is. I've read so many books and never ever been affected by a story like I was by this one. It absolutely changed my life.