IN THE belief that authors and potential authors may be helped by explicit statements of justification for author- ship, the following guidelines are offered for research pa- pers, case-series analyses, case reports, review articles, and editorials. These guidelines are based on statements issued by the International Committee of Medical Jour- nal Editors (ICMJE) that were pubhshed recently (1-3) and will eventually be incorporated into the Committee's document, "Uniform Requirements for Manuscripts Sub- mitted to Biomedical Journals" (4, 5). The ICMJE statements on authorship represent five principles that are applied below in the specific guide- lines. (These principles have been developed directly from the ICMJE statements with some clarifications.) Principles for Authorship Principle 1. Each author should have participated suffi- ciently in the work represented by the article to take pub- lic responsibility for the content. Investigators in the sciences and others who use scien- tific information must have confidence in its accuracy and validity. Such confidence rests in part on knowing that at least one person has taken public responsibility for the information, and for published information the re- sponsible persons are authors (6, 7). "Public responsibili- ty" means that an author can defend the content of the article, including the data and other evidence and the conclusions based on them. Such ability can come only from having participated closely in the work represented by the article and in preparing the article for publication (7). This responsibility also requires that the author be willing to concede publicly errors of fact or interpretatio n discovered after publication of the article and to state the reasons for error. In the case of fraud or other kinds of deception attributable to one or more authors, the other authors must be willing to state publicly the nature and extent of deception and to account as far as possible for its occurrence.