Those who have listened to Spirit's "Taurus" and hear similarity to the opening guitar riff in "Stairway to Heaven" might expect Led Zeppelin to be in trouble at a copyright trial scheduled for May 10. However, don't bet against Led Zeppelin just yet. On Monday, the defendants scored some key victories that will severely limit the testimony and evidence heard by a jury.

Perhaps most important, U.S. District Judge R. Gary Klausner has decided to exclude many of the "Taurus" sound recordings that the Randy Craig Wolfe Trust (which counts itself as a beneficial owner of Spirit member Randy California's works) wanted to play for the jury. The "Taurus" copyright is limited to what was deposited with the Copyright Office in 1967 and so the judge has agreed with Led Zeppelin that the only recordings to be presented for the jury's ears are the ones transcribed from the copyrighted sheet music.

What's more, the judge has rejected all of the plaintiff's experts because these musicologists prepared their reports and opinions by relying upon sound recordings that embodied unprotected performance elements.

That's not to say for sure that the Randy Craig Wolfe Trust won't have any experts testifying. Judge Klausner has given the plaintiff five days to submit new expert reports "purged" of what's unprotected.

Led Zeppelin's pretrial victories hardly stop there.

The band also has gotten the judge to bar any testimony on how Led Zeppelin has a history of plagiarism. The jury also won't hear about the wealth of Jimmy Page and Robert Plant. Nor will jurors be able to consider how Led Zeppelin bandmembers used drugs and alcohol. The plaintiffs wanted to use evidence of the latter to throw doubts on Page's recollection that he never heard Spirit's "Taurus" when composing "Stairway to Heaven." In fact, the judge also won't let the jury consider the many newspaper articles and book excerpts that addressed Led Zeppelin's alleged lifting of songcraft except for two statements made by Page in magazine interviews. When Page testifies (more on that in a moment), the Randy Craig Wolfe Trust will attempt to use his prior recollections to impeach him.

As for what the plaintiff wished to exclude at trial, Klausner has decided not to let Led Zeppelin challenge the validity of Randy Craig Wolfe Trust, but will let the defendant introduce evidence that the "Taurus" copyright is actually owned by Randy California's son, Quinn Wolfe, instead of the Trust.

At a hearing yesterday, Francis Malofiy, attorney for the plaintiff, reportedly spoke of his concern that Page and Plant wouldn't present themselves to testify. The judge may not have the authority to order the two U.K. citizens to the trial. On the other hand, both have undergone depositions that will likely be played for the jury, assuming there's no settlement in the next two weeks that avoids a trial.