This is the best secular book we know of on teamwork. It is based on the authors' extensive study of many different types of teams. It is filled with case studies of successful teams, and describes the discipline of teamwork excellently. - available from Amazon Books or Alibris
Jones, Gordon, and Rosemary Jones. 1995. London: Scripture Union.
This is the single best book from a Christian perspective and the best book overall. Easy to read and packed with helpful insights.
Why teams don't work: What went wrong and how to make it right
Robbins, Harvey, and Michael Finley. 2000. London: Texere
This is not a happy-clappy everything-will-be-alright book about teams. It is realistic and makes it clear that teams are not the best option for every situation. The authors do believe, however, that working in teams can be very effective under certain conditions. They describe and explain how to overcome ten major problems in teamwork, such as Bad decision making, Uncertain boundaries, Unresolved roles, Toxic teaming atmosphere, Misplaced goals and confused objectives.
Teamwork: What must go right / What can go wrong
Larson, Carl E., and Frank E. Lafasto. 1989. Newbury Park, CA: SAGE Publications.
If you want an easy-to-read short book on teamwork from a secular perspective, this is it. The authors' research led them to compile a list of eight characteristics of effective teams. Their description of these characteristics is very helpful- available from Amazon Books or Alibris
Best Books for ALL Church Planters