Not only does baptism of the dead not appear in The *Book of Mormon, *the book makes it clear that those who die as non-Mormons go to hell, period:
“For behold, if ye have procrastinated the day of your repentance even until death, behold ye have become subjected to the spirit of the devil, and he does seal you his. Therefore, the spirit of the Lord has withdrawn from you and hath no place in you; the power of the devil is over you, and this is the final state of the wicked.” (Alma 34: 35-36)
This definitely does not leave open the possibility of a later, vicarious admission into the Mormon church.
And again:
“And it shall come to pass that when all men shall have passed from this first death unto life, insomuch as they have become immortal, they must appear before the judgment seat of the Holy One of Israel, and then cometh the judgment and then must they be judged according to the holy judgment of God. For the Lord God hath spoken it, and it is his eternal word, which cannot pass away, that they who are righteous shall be righteous still, and they who are filthy shall be filthy still; wherefore, they who are filthy . . . shall go away into everlasting fire, prepared for them; and their torment is as a lake of fire and brimstone, whose flame ascendeth up forever and ever and has no end.”
So, even the
Book of Mormon agrees that those who baptise by proxy are wasting their time.
catholic.com/library/mormonism_baptism_for_the_dead.asp
watchman.org/lds/baptdead.htm