>>> Check to see whether the prior art reference explains every element of a claim in the patent. If so, the reference “anticipates” the claim, and the claim is invalid.<p>I'm not a lawyer, but I have over a dozen patents, and have participated in other IP related activities such as invalidation. Here is how I understand it, as explained to me:<p>It's assumed by default that the patent is granted in light of the information referred to by cited works. In other words, the examiner has declared that nothing in the references anticipates the claims. If you're looking for new prior art, it has to be outside of those references.<p>Of course anything can be challenged, but instead of "look, we found some prior art," you have to argue, "look, the examiner missed something."<p>OP, does that make sense?<p>A couple other thoughts: First, the body text may be gibberish, but the body of patent A can be used against the claims of patent B, if A is not cited by B. I've used this successfully, thanks to a few solid days of Google searching. Or, A and C can be combined to show obviousness.<p>Second, body text can contain useful information in its own right. I have a product under development right now for my side business, using an electronic circuit described in an expired patent.