Trinity Church in Redlands, California, put together a Missionary Care Team which has been developing a system of proactive care for their missionary families since 2008. In this book they share their firsthand accounts along with results of their research on missionary care. Mind the Gaps is designed to equip your church with tools to create your own system of proactive care and reduce burnout and attrition.
A few things about this book are unusual. It's written by a committee, rather than a single author. It's written by and for church leaders, rather than from industry professionals. It also covers a broad array of related topics: everything from recruiting a missionary care team and establishing a philosophy of ministry to predicting missionary success and evaluating mission agencies, as well as more traditional topics of missionary care such as meeting spiritual, emotional, and practical needs and walking with missionaries through transitions.
The result is a bit overwhelming, and maybe especially for churches that don't have a mission pastor and a strong mission committee like Trinity's. For example, there are a lot of sentences that include phrases like "Your job as a missionary care team is..." when relatively few churches would have such a thing as a missionary care team, even if they have a missionary care effort. And of course many churches have neither and are trying to get started.
On the other hand, the book covers so much ground and provides so many practical tips that even if your church has a well-developed strategy for missionary care, there's probably something here that you can use.
So, four stars for an ambitious attempt at filling a "gap," but I think I'm going to have to give disclaimers when I recommend it.