If you are interested in why there are so many different denominations in Christianity and why so many types of church "models" (to use term of Jesuit theologian Avery Dulles) this is an excellent and resourceful introduction. This was the only book that I could find on the topic of comparative ecclesiology and was glad that the author approached this field from a very broad perspective.
Veli-Matti Karkkainen, is a Finish theologian that teaches at Fuller Theological Seminary and is of the Pentecostal persuasion. His evangelical association does not show through this theological comparative work. His sense of condensing ideas, analysis, and conclusions are very objective, erudite, and extremely fair. He also covers a lot of teritory and a broad perspective that many evangelicals would not feel comfortable with. Truly a great work of a scholarly theologian.
The sub-title "Ecumenical, Historical, and Global Perspectives" represents the organization of this study. The first section discusses in six chapters standard "Ecclesiological Traditions": Eastern Orthodox, Roman Catholic, Lutheran, Reformed, Free Church, Pentecostal/Charismatic and one extra chapter discussing the Church as One and contemporary ecumenical work between the various traditions.
The second section, "Leading Contemporary Ecclesiologists" discusses the works of the best theologians representing the six traditions discussed in the first section. John Zizioulas representing Eastern Orthodoxy speaks of the Church as "instituted" by Christ and "constituted" by the Spirit. Hans Kung sees the Church (from his earlier Roman Catholic perspective) as "the people of God," the whole ecclesia, and the whole fellowship of the faithful. Wolfhart Pannenberg, uses his Lutheran background to come to an ecumenical understanding. Thus Pannenberg sees "the church as pointing beyond itself to the final purposes of God" - "the unity of all people of God under one God." Jurgen Moltmann's (Reformed) relational ecclesiology emphasizes "that the church never exists for itself but is always in relation to God and the world" because "the mission of the church in not to spread the church but to spread the kingdom." Croatian Miroslav Volf (Yale professor) "seeks to suggest a viable understanding of the church in which both person and community are given their proper due." James McClendon Jr. (Baptist) characterizes "the church gathering is God's gathering" and "Christ's presence is to be expected among his gathered people wherever that may take place." Lesslie Newbigin (Anglican) approaches ecclesiology with three catchwords: missionary, ecumenical, and dynamic, and his key motto is "no church without mission, and no mission without the church."
The third section, "Contextual Ecclesiologies" looks at contemporary ecclesiologies that have a cultural or geographical origin and do not fit into a particual traditional mold. Thus the non-church movement in Asia (especially Japan), the base ecclesial communities (CCBs) of Latin America, the African Independent Churches, Shepherding Movement, feminist church, world church, and Barry Harvey's post-Christian church as "Another City" receive their individual place in this study with insightful analysis.
While Veli-Matti Karkkainen states that this introduction is by no means comprehensive, I benefited greatly by understanding many traditions' and other contemporary views of what makes church church. Now I am aware of more theologians and writings on the topic of ecclesiology.
The common thread running threw all these views is that the church is "a community with purpose and hope for the future", and "a fellowship of men and women, a fellowship of the Spirit, a koinonia."