The Mormons have a special reason for their need of genealogical information. It is called the ancestor’s proxy baptism. Since 1840 people who have already died can be baptized, with a living family member as a proxy for the deceased. This form of baptizing is limited to the Mormons only.
To conduct an ancestor’s proxy baptism there has to be an enormous source of genealogy information. That’s why the Mormons have these huge collections of records. Nowadays the church has a very big database, known as the International Genealogical Index or IGI, which is open to the public through their Family Search website.
When you do a search in the IGI you start with a data form, which is easy to use and to put data in. The database searches are based on the name of a deceased individual, his parents and spouse’s names, and date and place of birth.
Even just the person’s name and location can be the starting point of a search. Basically the IGI is an enormous index of surnames that are on record in the Family History Centers and the website.
Now that you know why Mormons have such an interest in genealogy you might think most of their records are about Mormons. Yes and no; of course it is set up for the church members, but the collections have many resources with non-Mormon people, perhaps even your own family member(s). Since the size of the database and all the details it contains, searching it may be a bit annoying, but can be very fruitful.