This special issue provides anchor points of knowledge in the broader landscape of online learning. Most of the authors have situated their systematic reviews in the context of earlier systematic reviews of online learning. When examining well-established research areas, they nest their findings into existing gaps or extend earlier reviews. Other reviews represent forays into newer areas where research has yet to fully mature; in effect, they offer an initial vision of what is known and how future studies might connect and extend some of the earlier research. In the spaces between these systematic reviews and the ones that came before them are gaps that remain to be filled. Some of these holes represent knowledge about directly related parallel topics (e.g., research on different learner groups or different pedagogical strategies), while others represent complementary topics (e.g., online learning technology, policy, and administration).

Beyond the content-focused insights offered by these systematic reviews, the articles also serve as models for future online learning reviews. They demonstrate varied ways of viewing and synthesizing a body of related research, including the use of existing frameworks, development of new thematic coding systems, and examinations of time, trends, and even cocitation. They provide methodological guidance and leave ledges onto which future researchers can develop future studies with meaningful foundations as well as update these reviews as years pass and additional research is conducted and published. Future researchers are encouraged to also focus on meso-level topics such as management, organization, and technology as this special issue did not include any studies on them.

Our hope is that readers enjoy the nine articles found in this special issue and utilize their insights in their own future research, teaching, or research translation efforts. Whatever your intended use or situation, we wish that you find this issue informative and beneficial. Given that the application and impact of online learning during the coming decade will likely continue the rapid pace set in the previous ones, there will be assorted uses and applications, many of them unintended or unplanned, of this issue of online learning research as well as the many such journal issues to follow.