What is the single best book to read that has such a profound impact that you will quit porn forever?

>>24524732 (OP)
I'd love to hear your thoughts on this Mark Twain excerpt from Following the Equator-

"He had often taken
the pledge to drink no more, and was a good sample of what that sort of
unwisdom can do for a man—for a man with anything short of an iron will.
The system is wrong in two ways: it does not strike at the root of the
trouble, for one thing, and to make a pledge of any kind is to declare
war against nature; for a pledge is a chain that is always clanking and
reminding the wearer of it that he is not a free man.

I have said that the system does not strike at the root of the trouble,
and I venture to repeat that. The root is not the drinking, but the
desire to drink. These are very different things. The one merely
requires will—and a great deal of it, both as to bulk and staying
capacity—the other merely requires watchfulness—and for no long time.
The desire of course precedes the act, and should have one's first
attention; it can do but little good to refuse the act over and over
again, always leaving the desire unmolested, unconquered; the desire will
continue to assert itself, and will be almost sure to win in the long
run. When the desire intrudes, it should be at once banished out of the
mind. One should be on the watch for it all the time—otherwise it will
get in. It must be taken in time and not allowed to get a lodgment. A
desire constantly repulsed for a fortnight should die, then. That should
cure the drinking habit. The system of refusing the mere act of
drinking, and leaving the desire in full force, is unintelligent war
tactics, it seems to me. I used to take pledges—and soon violate them.
My will was not strong, and I could not help it. And then, to be tied in
any way naturally irks an otherwise free person and makes him chafe in
his bonds and want to get his liberty. But when I finally ceased from
taking definite pledges, and merely resolved that I would kill an
injurious desire, but leave myself free to resume the desire and the
habit whenever I should choose to do so, I had no more trouble. In five
days I drove out the desire to smoke and was not obliged to keep watch
after that; and I never experienced any strong desire to smoke again. At
the end of a year and a quarter of idleness I began to write a book, and
presently found that the pen was strangely reluctant to go. I tried a
smoke to see if that would help me out of the difficulty. It did. I
smoked eight or ten cigars and as many pipes a day for five months;
finished the book, and did not smoke again until a year had gone by and
another book had to be begun.

I can quit any of my nineteen injurious habits at any time, and without
discomfort or inconvenience. I think that the Dr. Tanners and those
others who go forty days without eating do it by resolutely keeping out
the desire to eat, in the beginning, and that after a few hours the
desire is discouraged and comes no more."