The Wall Street Journal today has an excellent, although troubling look at ghostwriting. That is, researchers who do the work don't actually write the research results in papers submitted to journals.
Sometimes the "ghostwriting" is not disclosed. Oftentimes the ghostwriter is hired by a drug company whose product is the subject of the research.
One journal editor tells the story of a paper that was submitted but the "track changes" function of Word was still in place. It showed that the "author" really didn't write the article. And a telltale note was in the text: "Marketing approval required."
This is an ethical issue that journals and the scientific community must deal with.