Archaeopteryx lithographica might be regarded as the most important zoological species known, fossil or recent. Its importance lies not in that its transitional nature is unique-there are many such transitional forms at all taxonomic levels-but in the fact that it is an obvious and comprehensible example of organic evolution. There have been recent allegations that the feather impressions on Archaeopteryx are a forgery. In this report, proof of authenticity is provided by exactly matching hairline cracks and dendrites on the feathered areas of the opposing slabs, which show the absence of the artificial cement layer into which modern feathers could have been pressed by a forger.