What book will significantly improve your life if you apply it?

Not a book but can be learned via YouTube.

The Wim Hof Method. Benefit: never feel unhappy because it’s cold ever again. Much less relevant benefit: you can now get free drugs at parties (it produces a lot of adrenaline when you do it, more than peak bungeejumping [1]). Or as a temporary pain killer, but you need to keep doing it.

Warning: do your own research [2]. Do not use it while diving (people died). It is not a free diving technique, no matter what anyone says. Train with someone watching you. Also consult your doctor before doing this, erring on the safe side here.

Disclaimer: Msc. Computer Science (aka not a doctor). I do know the WHM since 2014 and have done crazy trials with the legend himself. I checked some YouTube courses and they teach the fundamentals needed.

1. See their PNAS publication on WHM.

2. Doctor’s opinion: https://m.youtube.com/watch?v=D6EPuUdIC1E

I don't think it works for everyone, but I've read a lot of good from people religiously applying the GTD[0] method. Though it is a very strict method and a lot of people will get discouraged quickly when trying to apply it.

[0] Getting things done - David Allen https://gettingthingsdone.com/

Freedom from the Known by Jiddu Krishnamurti, but you won't apply it.

How to win friends and influence people.

The Way to Love by Anthony DeMello

The Path to Nibbana, by David Johnson.