Do contemporary people have fewer friends than they used to? In this entry, we examine the research on strong tie networks, or networks containing people especially important to us, in order to provide a partial answer. We begin with a review of the methods employed to collect data on social network connections. We then summarize the literature on the size of Americans' social networks as well as change in this size over time. Finally, we conclude with an analysis of where the study of strong networks needs to go and some suggestions for getting it there. Overall, the research suggests that while strong networks have changed over the past 30–40 years, and may be smaller overall, people are no more isolated than they were in the past.