A summary is a condensed version of a document. It contains the most relevant information in context found in the source document. Automatic summarization is the process of producing text summaries by computer. Although research on automatic summarization started in the late 50s, the increasing volume of electronic text and recent international evaluation efforts have fuelled research in this field. The paper gives an overview of basic concepts in automatic text summarization together with examples of available tools, systems, evaluation, summarization experiments, summarization in practical settings, and discusses the role of linguistic information in the summarization task.