Employment systems consist of complex arrays of formal and informal rules that structure the relationships between employees and employers. There are many different types of employment systems. Some are specified in considerable detail in collectively bargained quasilegal employment contracts, while others are left to discretion. This book describes the latter type of employment system-one in which there is an active market for knowl­ edge and skills. This is the salaried employment system of ForestCo-a large multiplant manufacturing company in the forest products industry. Here, supervisors and managers actively adjust the jobs and persons under their authority to meet the market, social, and institutional forces that influence the activities and performance of their departments. The study of employment systems is a relatively recent phenomenon, and few prior studies or theories were found to guide this investigation. Neither the scope nor the components of employment system studies are yet established. The field is confused and contested. Nevertheless, there is related literature which can be used to focus attention on different features of employment systems. One emerging body of work that holds the most promise for the study of employment systems is internal labor market (lLM) theory.