Publication of manuscripts in a peer-reviewed journal often takes weeks, months or even years from the time of initial submission, because manuscripts must undergo extensive reviewer critique. The need to quickly circulate current results within a scientific community has led researchers to distribute documents known as preprints, which are manuscripts that have yet to undergo peer review. The immediate distribution of preprints allows authors to receive early feedback from their peers, which may be helpful in revising and preparing articles for submission.
Since 1991, preprints have increasingly been distributed electronically on the Internet, rather than as paper copies. This has given rise to massive preprint databases such as arXiv.org and to institutional repositories.
Stages of printing 
While a preprint is an article that has not yet undergone peer review, a postprint is an article which has been peer reviewed in preparation for publication in a journal. Both the preprint and postprint may differ from the final published version of an article. Preprints and postprints together are referred to as e-prints or eprints.
The word reprint refers to hard copies of papers that have already been published; reprints can be produced by the journal publisher, but can also be generated from digital versions (for example, from an electronic database of peer-reviewed journals, such as EBSCOhost), or from eprints self-archived by their authors in their institutional repositories.
Tenure and promotion 
In academia, preprints are not likely to be weighed heavily when a scholar is evaluated for tenure or promotion, unless the preprint becomes the basis for a peer-reviewed publication.
Preprint server by research field 
arXiv – physics 
The e-print archive arXiv.org (pronounced "archive") was created by Paul Ginsparg in 1991 at Los Alamos National Laboratory for the purpose of distributing theoretical high-energy physics preprints. In 2001, arXiv.org moved to Cornell University and now encompasses the fields of physics, mathematics, non-linear science, computer science, and quantitative biology. Within the field of high-energy physics, the posting of preprints on arXiv is so common that many peer-reviewed journals allow submission of papers from arXiv directly, using the arXiv e-print number.
In some branches of physics, the arXiv database may serve as a focal point for the many criticisms made of the peer review process and peer-reviewed journals. In his column in Physics Today, April 1992, David Mermin described Ginsparg's creation as potentially "string theory's greatest contribution to science".
Nature Precedings – biology, medicine, chemistry, earth science 
Nature Precedings was a free electronic repository for preprints of scientific manuscripts, posters, and unpublished observations. It was operated from 2007–2012 by Nature Publishing Group.
Philica – any fields 
See also Open peer review
Sciencepaper Online – any fields 
Sciencepaper Online is a website approved by the Ministry of Education (China) and under the administration of the Center for Science and Technology Development of the Ministry.
The Social Science Research Network is a repository for both working papers and accepted papers, which shows download and citation data within the site for each stored paper.
ViXra – any fields 
Computer preprints 
The ability to distribute manuscripts as preprints has had a great impact on computer science, particularly in the way that scientific research is disseminated in that field (see CiteSeer). The open access movement has tended to focus on distributed institutional collections of research, global harvesting, and aggregation through search engines and gateways such as OAIster, rather than a global discipline base such as arXiv. E-prints can now refer to any electronic form of a scholarly or scientific publication, including journal articles, conference papers, research theses or dissertations, because these usually are found in multidisciplinary collections, called open access repositories, or eprints archives.
See also 
- Cryptology ePrint Archive
- List of academic journals by preprint policy
- "Self-archiving FAQ". EPrints.
- Eysenbach G. "The impact of preprint servers and electronic publishing on biomedical research". Curr Opin Immunol. 2000 Oct;12(5):499–503
- Eysenbach G. "Challenges and changing roles for medical journals in the cyberspace age: Electronic pre-prints and e-papers". J Med Internet Res 1999;1(2):e9
- Electronic Preprints and Postprints, in Encyclopedia of Library and Information Science. Marcel Dekker.
- Inefuku, Harrison W. "Pre-Print, Post-Print or Offprint? A Guide to publication versions, permissions and the digital repository." Ames, IA: Digital Repository @ Iowa State University, 14 January 2013.
- Journal policies on preprints from Nature Precedings forum
- Pre-print, post-print, definitions and terms as defined by SHERPA (organisation)
- Preprint, Postprint as defined by Crossref