Newcomers to jazz often ask: Is it true that jazz is all improvised? Somehow the casual and romantic notion that jazz is generated in an entirely spontaneous manner has become deeply rooted in our society. The notator of any jazz solo, or blues, has no chance of capturing what in effect are the most important elements of the music. . . . A printed musical example of an Armstrong solo, or of a Thelonious Monk solo, tells us almost nothing except the futility of formal musicology when dealing with jazz. The difficulty of applying standard infringement measures to musical compositions in a way that will properly protect the plaintiff’s original expression and the defendant’s freedom to create original expression of his own may explain why courts have occasionally swerved from one pole to another and why even the most experienced judges have committed fundamental errors in these cases. The testimony of an expert upon such issues, especially his cross-examination, greatly extends the trial and contributes nothing which cannot be better heard after the evidence is all submitted. It ought not to be allowed at all; and while its admission is not a ground for reversal, it cumbers the case and tends to confusion, for the more the court is led into the intricacies of dramatic craftsmanship, the less likely it is to stand upon the firmer, if more naive, ground of its considered impressions upon its own perusal. We hope that in this class of cases such evidence may in the future be entirely excluded, and the case confined to the actual issues; that is, whether the defendant copied it, so far as the supposed infringement is identical.