Educators consistently identify student motivation as a top concern, particularly during the transition to college, but often feel helpless to influence it. Some assume that students are simply motivated or not. Others are daunted by trying to shape an unobservable psychological phenomenon. "Invisible Forces" provides a framework for thinking of student motivation as a set of internal "mindsets" that are promoted or thwarted through a complex ecology of personal, classroom, institutional, and systemic factors. Using the method of portraiture, Pei Pei Liu brings this ecology to life. The book presents a series of four rich case studies of educators' efforts to support student motivation and the challenges they encounter in secondary and postsecondary writing classrooms. Attuned to the unique status of writing-based courses as a near universal academic experience throughout the transition from high school to college, these portraits shed light on different strategies, make a case for institutional support of instructors, and pave the way for greater alignment between secondary and postsecondary settings.