This document provides an overview of families and how they are changing. It discusses the fluid and diverse nature of families today compared to past generations. Families serve important functions like regulating sexuality, childrearing, economic support, and emotional support. However, what constitutes a family continues to evolve due to broader societal transformations around topics like marriage and household composition. Racial/ethnic diversity is also increasing the variety of family forms in countries like the US. Both micro decisions within families and macro forces outside their control, like the economy, influence how families change over time.