Over the past decade postsecondary education has been moving increasingly from the classroom to online. During the fall 2010 term 31 percent of U.S. college students took at least one online course. The primary reasons for the growth of e-learning in the nation's colleges and universities include the desire of those institutions to generate new revenue streams, improve access, and offer students greater scheduling flexibility. Yet the growth of e-learning has been accompanied by a continuing debate about its effectiveness and by the recognition that a number of barriers impede its widespread adoption in higher education. Through an extensive research review, Bradford Bell and Jessica Federman examine three key issues in the growing use of e-learning in postsecondary education. The first is whether e-learning is as effective as other delivery methods. The debate about the effectiveness of e-learning, the authors say, has been framed in terms of how it compares with other means of delivering instruction, most often traditional instructor-led classroom instruction. Bell and Federman review a number of meta-analyses and other studies that, taken together, show that e-learning produces outcomes equivalent to other delivery media when instructional conditions are held constant. The second issue is what particular features of e-learning influence its effectiveness. Here the authors move beyond the "does it work" question to examine how different instructional features and supports, such as immersion and interactivity, influence the effectiveness of e-learning programs. They review research that shows how these features can be configured to create e-learning programs that help different types of learners acquire different types of knowledge. In addressing the third issue--the barriers to the adoption of e-learning in postsecondary education--Bell and Federman discuss how concerns about fraud and cheating, uncertainties about the cost of e-learning, and the unique challenges faced by low-income and disadvantaged students have the potential to undermine the adoption of e-learning instruction. Based on their research review, the authors conclude that e-learning can be an effective means of delivering postsecondary education. They also urge researchers to examine how different aspects of these programs influence their effectiveness and to address the numerous barriers to the adoption of online instruction in higher education. (Contains 69 endnotes.)