A literature review is the first and last steps of the research process, in that it entails continually reading about the topic on which you are working. In the past, the notion was that conducting a literature review meant to “read everything there is to read about your topic,” but with the immense volume of published research available in the world, that approach is neither functional, practical, nor necessary. A more practical definition is that you should read enough about your topic to satisfy a few basic requirements. The level of importance of these requirements may differ from one field of study to the next, but in all study areas, the basic few remain the same.

A literature review should: 

1. identify actual gaps in the accumulated knowledge base related to your field or study. (Problems or shortcomings with theories or findings.) This means you substantiate that and how your research contributes to the field of knowledge.
2. identify relevant theories in the field (and their shortcomings)
3. identify the “most widely accepted empirical findings”.
4. identify the dominant figures (people) contributing to the field.
5. identify research techniques frequently used (and their shortcomings).
6. identify and refine definitions.
7. help the researcher gain familiarity with terminology and style.
8. help the researcher gain familiarity with how research is presented in specific journals. 
9. be sensitive to the context in which other studies were done and the context in which the researcher’s own (current) study is done. 
10. reduce bias in your choice of information (i.e., be a balanced representation of the available knowledge).

Literature reviews are organised according to 7 main strategies (all context-dependent): 

1. Thematically
2. Historically
3. Research method(s)
4. Findings
5. Theories
6. Comparison and contrast
7. Any combination of the above (as long as it is a structured approach)
8. Less frequent strategies: alphabetically, geographically, according to main proponents. 

Using a combination of strategies and attempting to answer the 10 requirements will ensure that you synthesize (not just list) available knowledge to justify and situate your study in the broader academic knowledge base. 

The major types of literature reviews include Narrative (traditional), Systematic, Scoping, Integrative, and Rapid reviews.