The Public Library of Science (PLoS) is a nonprofit open-access scientific publishing project aimed at creating a library of open access journals and other scientific literature under an open content license. As of January 2008[update] it publishes PLoS Neglected Tropical Diseases, PLoS Biology, PLoS Medicine, PLoS Computational Biology, PLoS Genetics and PLoS Pathogens. PLoS ONE was launched at the end of 2006.
The Public Library of Science began in early 2001 as an online petition initiative by Patrick O. Brown, a biochemist at Stanford University and Michael Eisen, a computational biologist at the University of California, Berkeley and the Lawrence Berkeley National Laboratory. The petition called for all scientists to pledge that from September 2001 they would discontinue submission of papers to journals which did not make the full-text of their papers available to all, free and unfettered, either immediately or after a delay of several months. Some now do this immediately, as open access journals, such as the BioMed Central stable of journals, or after a six-month period from publication, as what are now known as delayed open access journals, and some after 6 months or less, such as the Proceedings of the National Academy of Sciences. Many others continue to rely on self-archiving.
Joined by Nobel-prize winner and former NIH-director Harold Varmus, the PLoS organizers next turned their attention to starting their own journal, along the lines of the UK-based BioMed Central which has been publishing open-access scientific papers in the biological sciences in journals such as Genome Biology and the Journal of Biology since late 1999.
As a publishing company, the Public Library of Science began full operation on October 13, 2003, with the publication of a peer reviewed print and online scientific journal, entitled PLoS Biology, and have since launched six more peer-reviewed journals. The PLoS journals are what they describe as "open access content"; all content is published under the Creative Commons "attribution" license (Lawrence Lessig, of Creative Commons, is also a member of the Advisory Board). The project states (quoting the Budapest Open Access Initiative) that: "The only constraint on reproduction and distribution, and the only role for copyright in this domain, should be to give authors control over the integrity of their work and the right to be properly acknowledged and cited."
 Business model
To fund the journal, PLoS charges a publication fee to be paid by the author or the author's employer or funder. In the United States, institutions such as the National Institutes of Health and the Howard Hughes Medical Institute have pledged that recipients of their grants will be allocated funds to cover such author charges. PLoS still relies heavily on donations from foundations to cover the majority of its operating costs. PLoS was launched with large grants from the Gordon and Betty Moore Foundation and the Sandler Family Supporting Foundation which combined made up 13 millions US dollars.
One criticism of charging author-side fees is that it fails to recognize the high cost of filtering and evaluating the high number of submissions the high-impact journals receive. To maintain standards, a strict review system is used that will in general lead to a large proportion of those papers that do not meet the (high) standards of a journal to be rejected for publication. Setting up and maintaining a review system requires substantial effort of both editors, editorial office and reviewers, and is hence one of the most costly elements of scientific publications.
The initiatives of the Public Library of Science in the United States have initiated similar proposals in Europe, most notably the "Berlin Declaration" developed by the German Max Planck Society, which has also pledged grant support for author charges (see also the “Budapest Open Access Initiative”).
 PLoS journals and their websites
- PLoS Biology  (launched in 2003) (ISSN 1544-9173)
- PLoS Medicine  (launched in October 2004) (ISSN 1549-1676)
- PLoS Computational Biology  (June 2005) (ISSN 1553-7374)
- PLoS Genetics  (in July 2005) (ISSN 1553-7404)
- PLoS Pathogens  (September 2005) (ISSN 1549-1676)
- PLoS Clinical Trials  (May 2006) (ISSN 1555-5887)
- PLoS ONE  (December, 2006) (ISSN 1817-101X)
- PLoS Neglected Tropical Diseases (ISSN 1935-2735)
(all ISSNs are "EISSNs", for the electronic edition)
 See also
- ArXiv.org e-print archive
- BioMed Central
- Creative Commons
- Open access
- Open Archives Initiative
- Self Archiving