A Ph.D. literature review is a critical assessment of the literature in your research field and related to your specific research topic. It is an essential part of a thesis, which can either be a standalone chapter or part of the introduction.
It is an overview of the published academic articles, books and book chapters on matters relevant to your Ph.D. research topic. Literature review also includes all of the major publications, but it does not need to include everything that has ever been published on the topic.
It is important that literature review critically evaluates the research that it covers; it shouldn’t simply describe other people’s work. It is therefore necessary to think critically about the literature as you read and make notes that are analytical rather than descriptive. Consider: