A. Collateral relatives include your ancestors' siblings, uncles, aunts, cousins and even in-laws. The importance of researching these relatives varies with the project, but studying them is always appropriate.

When you research collateral relatives, you often learn more about your own ancestors. A diary or family Bible may contain details on extended family, with dates, places and ancestral names. Collateral relatives often migrated together and settled near one another, and sometimes intermarried, named children for one another, worshipped and went to war together, and were buried in the same vicinity.