Tertiary source documents are materials that compile and summarize information from primary and secondary sources. They provide an overview of a topic, making it easier for researchers to find relevant data without delving into original studies or detailed analyses. Examples include encyclopedias, textbooks, and bibliographies. These sources are useful for gaining a general understanding of a subject, such as history, science, or literature. However, they are not considered authoritative for in-depth research, as they may lack the original context and detail found in primary sources like research articles or interviews.