If IP litigation is down, don’t blame Mike McKool. He’s doing his best to keep work flowing. On Tuesday the founding partner of McKool Smith filed a patent infringement suit in Tyler, Texas, federal court against more than 20 of the best-known companies in the Fortune 100, including Amazon, Citigroup, Google, Apple, and Staples. McKool’s client, Eolas Technologies, claims that the defendants have infringed two of its patents on technology allowing interactivity on the Web. Read the complaint here.

The name Eolas should ring a bell. Back in 2004, the company won a $565 million judgment against Microsoft for one of the patents being asserted in the current action. On appeal, the Federal Circuit upheld the jury’s finding of infringement and the damages award, but found the trial court had erred in not allowing certain evidence of prior art. The case was sent back for a retrial, but a confidential settlement was reached before a new trial could get underway.

McKool said the finding of infringement and validity of Eolas’s patent in the Microsoft case gives him reason to be upbeat. (Eolas was represented by Robins, Kaplan, Miller & Ciresi in its case against Microsoft.) The Federal Circuit’s finding that certain evidence was wrongly left out didn’t bother him.

“We don’t think [including the evidence] would have made any difference,” said McKool.

McKool said he’s also encouraged by the fact that the Patent and Trademark Office has upheld one of the allegedly infringed patents on three separate occasions.