Understanding the lives of our ancestors includes knowing what they did for a living. The major source of information is Census Records, which indicate each individual's occupation. Newspaper Obituaries and City Directories usually mention a person's occupation and sometimes also indicate the name of the company or organization where they worked.
Genealogists often search for employment records expecting to find personnel files filled with background details about their ancestor. Unfortunately, in the past, most employers and companies did not keep files on employees. Usually, the only records created regarding staff were pay ledgers that listed names, the number of days worked and the amount paid.