A number of categories have a separate introduction, marked by the category Introductions on topics.
Of special interest, perhaps, are the new publications* within the field.
Some of the topics include many resources. Two types of resources are helpful, especially if one is a newcomer: Scholarly commentaries are important for many reasons. Most have good bibliographies, some have a remarkable number of references.
General introductions are helpful, as they provide overviews and introductions to the content etc. I have not (yet) written a separate introduction to General introductions. Some of the subjects that is normally treated in such introductions do have a separate page: Genre, structure (or form*), the symbolism and imagery of Revelation, the language of Revelation, dating,* and the function or purpose,* incl. paraenesis,* of Revelation. Textual criticism* also belongs to the important, introductory issues.
One of the most important topics is the use of the Old Testament. It has been a popular area of research for the last more than two decades, and it is essential for the interpretation of Revelation. The use of the Old Testament concerns methodology, but also theology.
The relations to the rest of the New Testament, of which it is a part, is also an area of research, but not as popular. More popular, however, is research into the relationship between Revelation and other ancient literature.*
The recipients of Revelation were expected to have a decent understanding of the Old Testament, but they were also living in Asia Minor, i.e. in the Roman Empire. Persecutions and the imperial cult were facts of life. It is, in my view, open to debate which role persecutions and the imperial cult should play for the interpretation of Revelation.
Historical issues cannot be neglected, but neither should the theological ones.* Some topics are singled out for special discussion: Christology and ecclesiology, i.e. the study of Christ and his church; eschatology, including the problem as to how one should interpret the ‘thousand years’ in Revelation 20:1-10.
Approaches used in Biblical studies in general are also employed in the study of Revelation. Rhetorical* and, especially, narratological* studies are important. The entire issue of methodology* is basic as in all sciences.
The history of interpretation and research* is important regardless of which Biblical book one studies. An important part of the history of research is the ancient commentators (an introduction is forthcoming) as well as medieval ones* or other commentators.
As I am a native Dane, and thus a Scandinavian, and was awarded my doctoral degree from the Norwegian Lutheran School of Theology, and as the Scandinavian languages are quite similar, I have chosen to include resources that are particularly relevant to Scandinavians or to those who want an overview of Scandinavian publications.
* Introductions not yet available.