Genealogy is the study of one's ancestors. It has special significance in the Church of Jesus Christ of Latter-Day Saints.
Mormons believe that after the death of Jesus Christ and the early apostles, the proper priesthood authority was taken away from the earth. This authority included baptism, the sealing power, among other things.
Between the years 1820-1840, the prophet, Joseph Smith received special authority from Jesus Christ, John the Baptist, and the apostles Peter, James, and John to perform baptisms, and other saving ordinances. Joseph also taught that God loved all people, and that those who had died before the restoration of this priesthood would be taught the gospel in the spirit world, and would have the opportunity to receive the same blessings as others born after the restoration of this priesthood. (See 2 Peter 3:18-19 and 1 Corinthians 15:29.)
Why is Genealogy Important?
Because of these teachings, mormons search records to learn more about their ancestors. These genealogical records allow living members to be baptized in behalf of their deceased ancestors in the various LDS Temples throughout the world. The church has helped improve genealogical research worldwide in support of these efforts.