Painless way to commit suicide?

Carbon Monoxide,

Basically the gas that's used in a gas oven :)
If you just leave the gas on till it fills the room, you eventually just fall asleep, and then suffocate painlessly in your sleep, look it up!

Most ovens these days cut the gas off if there's no flame though, so if you wanna put it in a book, make sure it's an old oven or something :)

Honestly there is no painful way to die. Pain is a part of life and it is a part of death as well....

Easy. Train to jump as high as you can, eventually, you'll be able to jump so high you'll be out of the earth's orbit and float off into space to die peacefully due to there not having any air there, unless you take an oxygen tank, which won't last long, but hey, who takes oxygen tanks into space anyway?

Jump off a tall building. Trust me. One of two things will happen: 1. You will pass out almost immediately after jumping from the shock of what you're about to do
2: You won't feel it at all when you hit.

During my time in South East Asia I fell off a 20ft roof and fractured my skull. The thing is I all I remember about that day is waking up, and next thing I know I'm in the hospital without a clue as to what happened and I'm hooked up to all these machines. Trust me you don't feel it and if I were to ever go out on my own accord I would hop off a building head first

For painless ways... Maybe drinking some poison and he will die painlessly....