Van Engen makes incorrect case at beginning for the church never really coming into its own, i.e. doing and being what it really is in this world and stage, thus some of the so familiar Biblical sounding tension of "now and not yet." Further, here he separates the church from kingdom of God, which is also an unbiblical move.
From this, he sequences to history of doctrine of the church, i.e. ecclessiology. Reviewing Roman Catholic and Reformed views primarily, he senses the inadequacy of four-fold concept: one, holy, catholic and apostolic church as well as the marks of the church method: Word, Sacraments, discipline (latter, betraying his Calvinistic orientation). Thus, he sequences all this history forgetting Lutheran ecclessiology which gives correctives to all these as well as Eastern Orthodox which he does not address either. From this, it is small step to modern ecclessiology which seeks to break out of this for more ecumenical, dynamic, mission orientation purpose for the church.
Thus, he arrives at book's purpose: the focus of local congregation.
While he provides much of Biblical view at times concerning Christ's church, he is too vague in his conclusions, i.e. confession.
As corrective to all this, interested theologians will pursue Kurt Marquart's monumental work "The Church: Her Fellowship, Ministry and Governance." He magnificently shows from the Bible and Lutheran Confessions how defective ecclessiology (as exhibited by Van Engen) comes from defective Christology--- "Is it possible to discern a pattern in the ecclesiologies of these major versions of Christianity? Without oversimplifying unduly, we may say the traditional Roman Catholicism (before Vatican II) particulary, but also Eastern Orthodocy, externalize the church, while Calvinism spiritualizes her. Lutheran theology, by its innermost logic, understands the church incarantionally."
Such a false division of visible and invisible church understood in wrong sense allows such ecclessiologies as Van Engen's to begin to put purpose of church back under law talk: what real congregations will and must do, rather than means of grace talk about God doing it all through the pure preaching of the Gospel and the right administration of the sacraments.
This book certainly provides one to realize where much of evangelical movement and Fuller is at concerning mission and ecclessiology, Christology, and where they want to make gignatic, non-static paradigm changes to effect more pragmatic numerical growth. Such not only ignores biblical realities, but will not comprehend theology of cross and rejection of truth, apostacy.
Summary : This book covered the theoretical and practical study on Church and Mission .Charles Van Engen gave an extensive and profound definition on the Church which covered from the biblical images , Church History and theological perspective (Part 1 , pp25-86).The Church is one ,is catholic ,is holy and is apostolic.But Charles Van Engen showed that the Church is also mission-intent for God's Kingdom because Christ's salvation and rule are in the Church and for the World .Therefore the church being the only earthly witness for Christ should engage its essence for the Great Commission (Part 2 , pp87-132) . Every local church is God's missionary people to reachout the whole world into the Lost. To accomplish such a mission task ,four elements in the local church : the Goal-setting , the mission-orientated members ,the commissioned leadership and the church administrative system will all be geared towards mission in passion and vision for the whole world (Part 3 , pp133-192).
Comment : Charles Van Engen's presupposition is that the Church in her essence cannot be divided or separated from her commission in mission to the world because the Church is the only chosen witness for Christ. But the issue is : Does the Church lose its essence when her earthly mission fails ? To make some analogy : (1) Does a man lose his image of God or his manliness if he fallen or paralysied ? (2) Does a cat lose its cat-ness if it loses its four legs and still alive ? My understanding is the Church is still the Church though she has not functioned her entrusted mission to the world . It is the same that Christ is the God in person even if he does not want to save his people on earth ! Because he is still the Lord if he did not be my Savior.