This chapter explores the frequency, types, and harms of fraudulent authorship, including ghosts, guests, gifts, and reciprocal authors. The frequent misuse of authorship continues, despite guidelines published by the International Committee of Medical Journal Editors. Misattribution of authorship has added to the concerns regarding the integrity of scientific publications. There is no doubt that the list of authors on scientific papers can influence the acceptance of papers by journals, and whether or not a grant application will be funded. As a result, misattribution of authorship can impact promotions and prestige. However, there is disagreement about the extent of these tactics, with one study showing that almost 18% of articles published in the top six medical journals had ghost authors. However, ghost authors were found in 75% of studies sponsored by industry. Given these variations, questions have arisen as to whether published guidelines have led to any substantial improvement in whether the guidelines on authorship have led to any substantial improvement in the listing of authors. In addition, increasing numbers of papers are claiming that all authors have contributed equally to the content, thus avoiding the recommendation that authors should take responsibility for specific sections of the research.