I think that most Christians would agree that the church should be missional. But what does that even mean? Is it about evangelism or social justice or both? Does missional activity happen in the church building or in the community or both? If you have been wrestling with these questions, you might enjoy The Mission of the Church edited by Craig Ott.
The Mission of the Church has the subtitle of Five Views in Conversation. The five views are Stephen Bevans (Roman Catholic), Darrell Guder (mainline), Ruth Padilla DeBorst (Latin American evangelical), Edward Rommen (Orthodox) and Ed Setzer (North American evangelical). In general I enjoy the five views style of books. I did like this book, but there was not as much disagreement as you would expect. There was a tremendous amount of overlap in positions. It was almost disappointing.
If you are interested in what it means to be missional, this is a great resource. The authors discuss issues as what the Trinity means for the mission of the church and the definition of Missio Dei. The interactions are very respectful and the different perspectives do help fill in questions people might have about a missional church.