Another important change has been a decrease in the importance of monks and monasteries. In much of Asia, Buddhism is usually divided between monks and laypeople, with the monks actively seeking enlightenment, and laypeople doing the best they can to lead an ethical life in the hopes of being reborn as something better in the next life.
In the West, the two lifestyles have largely become synthesized. Few are willing to actually enter a monastery for the rest of their lives, and almost all dedicated Buddhist monks come from Asia. At most, people attend monastery retreats for a couple of weeks in order to escape the distractions of modern life. In general, however, Buddhist practice has become more about living an ethically responsible life rather than retreating from life.
Buddhism presents a serious challenge to Western culture, whether Christian or secular. The whole structure of our culture and society is predicated upon the assumption that we are all unique, individual and autonomous selves that we have an identity based on things like religion, ethnicity, class, etc. Buddhism questions and even denies that premise, forcing people to re-examine who they might be and what they are doing.
Will traditional Christianity be up to this challenge? How will secular philosophies like humanism or objectivism respond? The first step to meeting this challenge is to understand the unique development of Buddhism in the West, and Colemans book will help you do it.