A literature review is a methodical or organized review of the published literature on a specific topic or research question designed to analyze--not just summarize--scholarly writings that are related directly to your research question. That is, it represents the literature that provides the context for your research and shows a correspondence between those writings and your own work.
The past few years have seen an explosion of online tools designed to automate the process of doing literature reviews. These tools generally work by asking you to identify a relevant article (often called a "seed article") and use the metadata attached to articles (such as authors and keywords), or citations and reference lists to find related articles. Most tools offer some type of visualization feature to trace the connections between papers, and increasingly, tools offer summaries of the research content. These tools provide researchers with an option to at least partially automate some of their literature review work which can save a lot of time.
Things to keep in mind:
NOTE: This is a rapidly evolving field and we will be updating this guide on a regular basis.