Tertiary sources are materials that compile and summarize information from primary and secondary sources. They provide an overview of a topic, making them useful for quick reference. Examples include encyclopedias, textbooks, and bibliographies. These sources do not present original research or firsthand accounts but instead organize existing knowledge. These sources are often used in academic settings to gain a general understanding of a subject before diving deeper into more detailed studies. They can help researchers identify key concepts, terms, and significant works related to topics like history, science, or literature.