The word "genealogy" refers to the discovery of a person's ancestry. Likewise, a genealogist is someone whose job is to trace lineage to discover related persons. Genealogists investigate family trees to determine who came from whom and to help form a more complete tree.
Genealogy may be important to people who want to know who their ancestors are and where they came from. Genealogy is also important when historians are trying to determine the descendants of famous or important people who lived long ago, such as Abraham Lincoln and George Washington. Genealogy can also help find a common ancestor shared with another living person even if that ancestor lived hundreds of years ago.