This is a very important book for the church today, particularly for those within the Free Church tradition. Jeff's work is born out of a deep concern for the visible unity of Christians as one of the primary ways the Church bears witness to the world.Therefore, one of his primary theological concerns deals with the increasingly visible effects of individualism within churches. Specifically where there is a lack of common understanding as to where `authority' lies in the church and how it functions. Those within free churches have typically located authority primarily (if not completely) with the Bible, whereas a majority of the church has historically recognized a constellation of distinct but not mutually exclusive modes of authority found in the Scripture, tradition and the teaching office of the church.Though recently, an increasing number of Free Church theologians are pressing for a deeper engagement with the wider theological and liturgical traditions of the church as authoritative [along with Scripture].But to say that the church should read scripture in light of the church's wider theological tradition opens up a new set of questions - most pressingly, `how is unity with this one church to be visibly demonstrated within a Free Church context in light of its traditional construal of authority?As Jeff notes in the book, often a solution to the problem of unity has been sought in the notion of the `invisible church' or the `church as God sees it'.But in recent years, protestant theologians have become increasingly dissatisfied construing church unity primarily in terms of invisible unity.This movement of thought is central to the book. In his own words: "The primary purpose of this study is to build on the recent turn to tradition among free church theologians primarily by pressing the question of visible ecclesial unity and its relationship to the issue of authority..."He continues, "can the contemporary pursuit of tradition as an authority be undertaken coherently apart from a demonstrative pursuit of visible unity beyond the local congregation, especially in the form of an authoritative extra-congregational teaching office of some kind?I shall argue that the one leads naturally to the other and that a rejection of a simplistic sola scriptura doctrine along with the affirmation of visible unity of the church substantiates and recommends the classic recognition of the triple loci of authority: Scripture, tradition, and some form of Episcopal teaching office."In order to facilitate these discussions in his book, Jeff begins by engaging in conversation with a number of prominent Free Church theologians such as John Howard Yoder, Stanley Grenz and D.H. Williams.He then brings into conversation two theologians outside of the Free Church tradition: Robert Jenson (a Lutheran theologian prominent for his effort in ecumenical dialogues in the last half of the century) and Rowan Williams (former Archbishop of Canterbury and an outstanding theologian in his own right). Jeff is primarily interested in how these two men understand the tri-loci of authority to function in the church in terms of visible unity. I would say here that each of these chapters are well worth the price of the book on their own!In the last core chapter, Jeff engages Free Church (Baptist) theologian James McClendon, who is recognized as a pioneer in discussions of unity amidst free churches.Jeff is not calling us to abandon our traditions or churches but rather he helps us to think more truthfully and faithfully about how we understand and practically work out the command for unity in the church. As a missionary, it is clear to me that this book should be read attentively by the church in any given location - as we all learn to be open to the Spirit's work in moving us towards greater communion and unity as a witness to the watching world.