We have changed our copyright and permissions policies to make it easier for authors and readers to use material published in PNAS for research or teaching. Our guiding principle is that, while PNAS retains copyright, anyone can make noncommercial use of work in PNAS without asking our permission, provided that the original source is cited. For commercial use (e.g., in books for sale or in corporate marketing materials), we approve requests on an individual basis and may ask for compensation. We have revised our copyright assignment form to make the changes clear (www.pnas.org/misc/copyright.pdf) and added to our web site a “frequently asked questions” (FAQ) section on author and reader rights (www.pnas.org/misc/authorfaq.shtml).

As a PNAS author, you automatically have the right to do the following:

1. Post a PDF of your article on your web site.

2. Post a webcast containing material from your article.

3. Make electronic or hard copies of articles for your personal use, including classroom use.

4. Use, after publication, all or part of your article in a printed compilation of your work, such as collected writings or lecture notes.

5. Include your article in your thesis or dissertation.

6. Reuse your original figures or tables in your future works.

7. Post a preprint of your article on a public electronic server, provided that you do not use the files created by PNAS.

8. Present your paper at a meeting or conference, including those that are webcast, and give copies of your paper to meeting attendees before or after publication in PNAS. For interactions with the media prior to publication, see the PNAS policy on media coverage (www.pnas.org/misc/forms.shtml).

9. Permit others to use your original figures or tables published in PNAS for noncommercial use (e.g., in a review article), provided that the source is cited. Third parties need not request permission to use figures and tables for such use.

Given that authors and readers can automatically use original material in PNAS for research or teaching, why do we request copyright transfer? We do so for three reasons: to allow us to publish, archive, and migrate articles to new media; to remove the administrative burden of rights and permissions management from authors; and to provide protection from copyright abuse.

We do not feel that this or any copyright policy is the only one possible. In fact, our policy has changed through our 90 years of publishing and surely will change again. We have requested that authors transfer copyright only since 1993. From the first issue of PNAS in 1915 through 1992, authors held copyright to their articles. From 1978 to 1992, we registered copyright for each journal issue as a collected work but did not request copyright for individual articles. In 1993, we began requiring that authors transfer copyright “in all forms, languages, and media now or hereafter known,” which granted us the rights to publish papers online in 1997 and to then digitize selected back issues and post them online.

We think that our current policy best meets the needs of readers, authors, and the journal, for the following reasons:

1. To store and migrate archival formats of the journal. We are committed to facilitating permanent, freely accessible archives of the scientific literature. PNAS is a charter member of PubMed Central, a digital archive of the life sciences journal literature (www.pubmedcentral.nih.gov), and is a participant in the National Library of Medicine's effort to digitize and post back issues of journals. Not holding copyright to individual articles from 1915 to 1992 delayed our posting of this older material online because we do not have the legal rights to do so. In the end we proceeded without explicit permission from the original authors or their heirs. We accept the risk in doing so because we believe it is clearly in everyone's best interest. If a copyright holder objects, however, we will immediately remove the article from our online collection. Full copyright transfer allows publishers explicit rights to invest in long-term archiving strategies.

2. To provide an administrative convenience for everyone. Despite our liberal rights and permissions policies, PNAS still receives more than 50 commercial and noncommercial permission requests per week. We routinely agree to noncommercial use, so such requests waste everyone's time.

   Unfortunately, PNAS cannot provide permission for others to use all or part of articles published from 1915 to 1992 because we do not hold copyright. Only the original authors or their designees can grant permission. Researchers are frustrated when they contact us for permission to use seminal works and we are unable to grant their requests.

3. To provide international protection regarding infringement or plagiarism. On the rare occasion that material is misused, authors appeal to PNAS to intervene on their behalf to enforce copyright protection. In such cases, a formal query from PNAS or the threat of a copyright infringement lawsuit has prompted expeditious action. In cases of redundant publication we sanction authors for violating journal and copyright policy. Because international standards and copyright law are complex, PNAS leaves interpretation of global copyright standards to our expert legal counsel.

We also support creative efforts such as charting, mining, analyzing, sorting, navigating, and displaying information contained in PNAS. The highly successful Sackler Colloquium “Mapping Knowledge Domains” (www.pnas.org/content/vol101/suppl_1) is a prime example (1). We encourage authors to use standard forms of data presentation to facilitate this process.