The Mormon afterlife is to be understood as the doctrine of what happens after one dies. The issues involved are very complicated, ranging from the salvation and evangelizing of the dead to the question of 'what is necessary to attain the celestial kingdom'.
"Heaven" in Mormonism is spoken of as three different "kingdoms" - the Celestial, Terrestrial, and Telestial.
"Hell" in Mormonism is sometimes referred to as outer darkness, other times as a temporary spirit prison, and other times even as the state of suffering and regret in the Telestial and Terrestrial kingdoms.
 Telestial Kingdom
Murderers, other criminals, and the like who do not accept the Atonement of Jesus Christ will eventually spend eternity with people of like intent in the Telestial Kingdom, and their glory will be as that of the stars in the night sky. This is also considered a kingdom of glory and has been described as being much better than earthly life. All those who do not qualify for a higher degree of glory will automatically enter this kingdom unless they deny the Holy Ghost, a sin it is believed very few people are able to commit.
- See main page: Telestial Kingdom
 Terrestrial Kingdom
Those good people who are not valiant in following Jesus or who do not accept the Gospel do not qualify for exaltation and will be consigned to the Terrestrial Kingdom (whose glory is compared to the brightness of the moon in the sky). This kingdom is one of great glory, but without the presence of God the Father. An ultimate willingness to keep the "law of carnal commandments" (the Ten Commandments) is considered essential to enter this kingdom.
- See main page: Terrestrial Kingdom
 Celestial Kingdom
The Celestial Kingdom (whose glory is compared to the brightness of the sun in the sky, as its inhabitants have all truth and light) is where the righteous will live with God and with their families. Those who have had the ordinances of eternal marriage, which is performed in Temples, and baptism may be exalted if they are found worthy by God. Accountable individuals must be baptized and repent to gain entrance to the Celestial Kingdom; Latter-day Saints profess that all children who die before the age of accountability automatically inherit a celestial glory.
- See main page: Celestial Kingdom
 Outer darkness
- "No progression between kingdoms. After a person has been assigned to his place in the kingdom, either in the telestial, the terrestrial, or the celestial, or to his exaltation, he will never advance from his assigned glory to another glory. That is eternal! That is why we must make our decisions early in life and why it is imperative that such decisions be right." (The Teachings of Spencer W. Kimball, p. 50)
- "On pages 420-21 of the first edition of The Articles of Faith, Talmage outlines the concept of progression between the kingdoms of glory in the hereafter, ending with this marvelous observation: "Eternity is progressive; perfection is relative; the essential feature of God's living purpose is its associated power of eternal increase." Talmage may have been influenced in his contemplations by Elder B. H. Roberts who had published a similar sentiment, but the way Talmage articulated it, it was the clearest expression yet of this doctrine and in a form that remains accessible to all members of the church." 
- "True, the Scriptures speak of endless punishment, and depict everlasting burnings, eternal damnation, and the sufferings incident to unquenchable fire, as features of the judgment reserved for the wicked. But none of these awful possibilities are anywhere in Scripture declared to be the unending fate of the individual sinner. Blessing or punishment ordained of God is eternal, for He is eternal, and eternal are all His ways. His is a system of endless and eternal punishment, for it will always exist as the place or condition provided for the rebellious and disobedient; but the penalty as visited upon the individual will terminate when through repentance and expiation the necessary reform has been effected and the uttermost farthing paid." (James E. Talmage, Vitality of Mormonism. 1919. Link)
- "The divine decree that disobedience and unrighteousness shall stop one's progress is known as "eternal damnation" (D&C 19:7; 29:44). Eternal means proceeding forth from God, for he is Eternal (D&C 19:10-12). And to be damned, said President Spencer W. Kimball, is to be "stopped in progress" (DSY 1976, 154)." - "Eternal Damnation" in Doctrine and Covenants Encyclopedia, by Hoyt W. Brewster Link
- "You have often heard me speak about my kindred...Will they be saved? Yes, they will, but they will be saved as I have told you many of these people will; they will first go the hell and remain there until the corruption with which they impregnated is burnt out; and the day will yet come when they will come to me and acknowledge me as their savior, and I will redeem them and bring them forth from hell to where I live and make them my servants; and they will be quite willing to enter into my service." - Hebert. C. Kimbal, Journal of Discourses 3:109
- “I think I am safe in saying that no man can become a Son of Perdition until he has known the light. Those who have never received the light are not to become Sons of Perdition. They will be punished if they rebel against God They will have to pay the price of their sinning, but it is only those who have the light through the priesthood and through the power of God and through their membership in the Church who will be banished forever from his influence into outer darkness to dwell with the devil and his angels. That is a punishment that will not come to those who have never known the truth. Bad as they may suffer, and awful as their punishment may be, they are not among that group which is to suffer the eternal death and banishment from all influence concerning the power of God” (Joseph Fielding Smith, Conference Reports, October 1958, p.21).
- “He is compassionate to all the works of His hands, the plan of His redemption, and salvation, and mercy, is stretched out over all; and His plans are to gather up, and bring together, and save all the inhabitants of the earth, with the exception of those who have received the Holy Ghost, and sinned against it. With this exception, all the world besides shall be saved. Is not this Universalism? It borders very close upon it” (Brigham Young, August 8, 1852, Journal of Discourses 3:92).
 See also
- Jacob J. argues that the Book of Mormon teaches a true heaven/hell dichotomy
- Perdition and the Three Degrees of Glory - Doctrine and Covenants 76:30-112; 131:1-4
- How Long Shall Hell Last?, by James E. Talmage (Vitality of Mormonism, 1919)
- What Is the Mormon Meaning of Hell?, by John A. Widtsoe (Improvement Era, 1951)
- The Reality of Hell and the Devil - 2 Nephi 28:22-25, by Robert L. Millet, Joseph Fielding McConkie (Doctrinal Commentary on the Book of Mormon, vol. 1)
- Damnation, by Daniel H. Ludlow (Encyclopedia of Mormonism)
- Damnation, by Bruce R. McConkie (Mormon Doctrine)
- Hell, compiled by Rulon T. Burton (We Believe)
- "Saved or Damned": Tracing a Persistent Protestantism in Early Mormon Thought, by Grant Underwood (BYU Studies, vol. 25, 1985)
- Going to Hell C. S. Lewis Style: His Views on Sin, Temptation, and the Devil, by Andrew C. Skinner, Robert L. Millet (C. S. Lewis, the Man and His Message: An LDS Perspective, 1999)
- How populous is Outer Darkness?, by Sam MB