Nucleic Acids Research (NAR) publishes the results of leading edge research into physical, chemical, biochemical and biological aspects of nucleic acids and proteins involved in nucleic acid metabolism and/or interactions. It enables the rapid publication of papers under the following categories: Chemistry and synthetic biology; Computational biology; Gene regulation, chromatin and epigenetics; Genome integrity, repair and replication; Genomics; Molecular biology; Nucleic acid enzymes; RNA and Structural biology. A Survey and Summary section provides a format for brief reviews. The first issue of each year is devoted to biological databases, and an issue in July is devoted to papers describing web-based software resources of value to the biological community.