This chapter outlines the main types of literature reviews used in epidemiology and public health research. It begins with an overview of reviews, describing different types such as narrative review, rapid review, scoping review, systematic review, and umbrella review, and explains their role in synthesizing existing evidence to address specific research questions. The concept of meta-analysis is then introduced, illustrating how statistical methods are applied to combine data from multiple studies to produce more precise effect estimates. Finally, the chapter examines network meta-analysis, which extends traditional meta-analysis by enabling comparisons across multiple interventions, even when they have not been directly compared in individual studies. Together, these approaches provide essential tools for summarizing evidence, guiding decision-making, and identifying gaps for future research.