The LDS believe that only persons baptized in their faith will be saved. Since they want all their ancestors to be saved, one of the things that they concentrate on is finding the people from whom they are descended so that they can be baptized in retrospect.
Each person in their faith has certain things that they have to do - they have to serve at the main temple, they have to do some 'recruiting', and they have to find their ancestors.
The result of this is that the Church of Latter Day Saints has one of the largest, if not THE largest library of records of this kind in the world.
3. Baptizing ancestors does not make them Mormon. It is viewed as a necessary "step" and baptized ancestors are not counted among the numbers or members of the church
Fondest memory: Most of the people working in the Family Library Center are volunteers, and they are patient and helpful.