Each of the sections in this chapter, which focus in turn on different steps of the review process, is structured in the same way. First, for a particular step, we summarize what is different when NRS (compared with randomized trials) are included in Cochrane reviews and, where applicable, describe conceptual issues that need to be considered. This first part includes relevant evidence, where there is some. Second, we summarize our guidance and, where available, describe existing resources that are available to support review authors.