The Art of Using Prior Art
"Prior art is typically a printed publication, patent, or patent application that has a publication or filing date prior to the filing date of the target patent. There are a variety of mechanisms/legal regimes that can be used to apply this prior art to invalidate a target patent. These mechanisms include: Protest, Third-Party Submission, Litigation, Reexam, and Citation to Prior Art. In addition to these existing mechanism, various projects and initiative relating to the use of prior art are under way. The purpose of these mechanisms, projects and initiatives is to ensure that true innovation is protected.
The question of what constitutes prior art can be confusing, to say the least. Moreover, the issue of when one can and cannot use a particular type of prior art in attacking the patentability of a particular invention is equally confusing...[This GROKLAW post] is a high-level outline of the some of the key concepts regarding what constitutes prior art, and how to apply it to address the patentability of an invention. The purpose of this primer is not to serve as formal legal advice, nor should it be considered as such. Rather, the purpose of this primer is to assist the general public, including those in the Open Source Community, with helping to improve patent quality."