Book review of Understanding Social Network This book offers a vast array of research-based concepts and theories of Social Network. The first of the four chapters introduce basic network concepts. Chapter 5 to 11 explores more concepts related to the field of psychology, organization, public health, and morality. In Chapter 12, Kadushin highlights “ten master ideas” mentioned in previous chapters and expressed his sincere hope for readers to conduct further research in Internet network, social capital, cultural and social difference. Understanding Social Network is no less than an enlightening material for whomever interested in social connections. Personally, this book helps me realize that we are no longer individual in this entire work. I start to reflect on the homophily and “small group" in my relationships with friends and colleagues. We may be unconsciously functioning as a weak tie or reach for help through weak ties. Most importantly, this book directs readers to a number of further studies. In Internet network, there are still many questions remain unsolved, such as whether there is cognitive limitation for Facebook users. But it is for sure that online network is no longer comprised of a bunch of unrelated strangers.