Cell is a peer-reviewed scientific journal which publishes novel research in any area of experimental biology that is significant outside its field. Areas covered include molecular biology, genetics, structural biology, biochemistry, cell biology, development, neurobiology and immunology in animals, plants, microbes and viruses. Founded in 1974 by Benjamin Lewin, it is published twice monthly by Cell Press, a division of Elsevier, from editorial offices in Cambridge, Massachusetts, USA. Cell had a 2007 impact factor of 29.887, which makes it one of the most cited scientific journals. According to ScienceWatch, the journal was ranked third in the Molecular Biology and Genetics category over 1999–2004, after only Science and Nature, with an average of 72 citations per paper. All articles are available online as PDFs via the journal website and ScienceDirect, with HTML versions additionally available from January 1996. Content over 12 months old is freely accessible from the January 1995 issue. Registration not required.