American faculty are changing. Approximately 65 percent of all faculty now being appointed are nontenure track. Despite these changes, many higher education institutions still operate as though tenure-track faculty are the norm and non-tenure-track faculty are a supplementary workforce. This monograph highlights practical and empirical tensions, reviewing theories and frameworks that have been applied to the study of non-tenure-track faculty in an attempt to better understand their emergence, experience, and outcomes. It also reviews the literature about key tensions that emerge because of the development of this new group of faculty: Is tenure still relevant and important? Can tenure-track and non-tenure-track faculty find shared interests to collectively create change? Can non-tenure-track faculty overcome competition that prevents them from working together meaningfully? Why is the research on the institutional and student impacts of non-tenure-track faculty so mixed? Does empirical research address stereotypes about non-tenure-track faculty and how can it be spread more widely to imporve institutional decision making? What future research is needed to guide policy? As a guide to the trends and research in non-tenure track faculty, this is an invaluable review for administrators and faculty who want to make better-informed decisions about staffing. This is the fifth issue in the 36th volume of the Jossey-Bass series ASHE Higher Education Report. Each monograph in the series is the definitive analysis of a tough higher education problem, based on thorough research of pertinent literature and institutional experiences. Topics are identified by a national survey. Noted practitioners and scholars are then commissioned to write the reports, with experts providing critical reviews of each manuscript before publication.