They go to many courthouses in search of probate records, county records, voter registrations, wills, death certificates, birth certificates, and deeds. Courthouses aren t the only source of data compiled by these diligent researchers. Genealogy is as old as the Bible. Adam is probably the only man known who spoke to all his ancestors face to face. Genealogy is a study and writing of family histories, making family trees if you please.
Genealogists are people who study and write genealogies.
The Bible contains the oldest and most accurate recorded genealogies in the old and new testaments. Royalty depended on a recorded list of descendants for succession to the throne. Even livestock raisers depend on pedigrees. My grandfather told me to always remember that God made man out of some dirt and He made women out of a second hand part. The last sentence was probably incorrect.