Having been a part of group evangelism in Brazil, brother Dickson writes Grouped in Groups from the standpoint of experience as well as careful study of the subject.  His book is one of the few on the market dealing with team efforts in the mission field, and it should serve as a worthy text for mission classes in our colleges as well as on the congregational level.  His logic is sound; his application of Scripture is excellent.  Please note the following example: "As long as two people exist upon the face of this good old earth, disagreement is going to hang around.  If you have ever been a missionary, you know what I'm talking about.  Every missionary has his own ideas of how it ought to be done.  Get two missionaries together, and sure enough, you have two ways in which one thing ought to be done.  The only problem comes in trying to decide who is going to give in.  Disagreement was what broke up one of the first group mission efforts (Acts 16:36).  However, that disagreement wasn't all bad, because two separate groups formed from that original split (Acts 15:39)."