Almost every organisation and their employees work in teams. Often, autonomous teams are presented and implemented as being the best practice for increased performance. Yet, when it comes to working in teams, there exists no single best solution. In this book a case is made for matching the task a team works on with the composition of that team, and vice versa. A theoretical model on the interactive effects of task characteristics and team composition on group processes and team performance is presented and tested. The model builds on previous research by defining team composition in terms of the Big Five personality inventory, and adds the level of task characteristics as a moderator on the relation between team composition and team performance. Results show that, especially when interdependence, autonomy and variety are high, it pays to carefully compose a team with suitable personalities. Conversely, when team composition is a given, this book details what type of task best fits a team. Application of this model and its results can offer management professionals new insights into how to increase performace from existing teams, and how to staff newly formed teams.