One is career related: I always keep coming back to the Cormen algorithms book because of its clarity and beauty of explanation. Sure, you can find explanations on places like geeksforgeeks, but they will never match the clarity of the former

Two fiction:

War and Peace: There's just has so much life in this book. The things you read, they age with you over time. I wish I could read it in the original

Ulysses: I don't know why I like this book tbh. There's a lot of "fluff" to it, but the parts that are good are so exceptionally good you will need to come back to them. I started reading the Wake a year ago and took a break bc busy. I still think about it though: he writes about culture like it's this drunken, surreal, fever dream. It's like you read it and wonder if this is how things actually are