As a result of Fresh Expressions/Emerging church and other mission initiatives, the term 'church' now covers an incredible variety of formal and informal congregations and networks - a dramatic shift from earlier understandings. Such change ushers in numerous practical and theological questions - when does an occasional gathering of a group of people in a caf#xE9;, bar, club, sports centre, or via the internet actually become a church? What characterizes a missional church? Is it different in essence and from a traditional church? This volume, the first in a series that will explore the spirituality and ecclesiology of new church communities, looks at the defining characteristics of fresh expressions of church. As the emergent church movement matures, these are essential questions that leaders in new and established churches alike need to be asking.