What does it really mean for the church to have unity?

When Jesus prayed for his followers to be one, he prayed that this unity would demonstrate the truth of his claims to an unbelieving world. Sadly, the world often sees a church that is divided. Some of our divisions are based on legitimate theological concerns, yet many others are simply matters of opinion. To the world, it's all another reason to doubt God.

What are the differences worth dividing over? How should we handle diversity?
Mending a Fractured Church, edited by Michael Bird and Brian Rosner, seeks to answer such questions, looking to the Bible for examples of how to behave when Christians differ. Speaking to pastors, churches, and seminary students, the contributors provide a guide to maintaining unity without compromise.