Music copyright infringement suits often involve little-known musicians seeking compensation from financially successful songwriters and performers, for alleged misappropriation of the intellectual content of musical numbers that were never published, or that enjoyed limited circulation. Judicial opinions typically turn on the court's musical analyses of the works in dispute, but these analyses are not meaningful to the reader of the opinions without audio and visual representation of the musical numbers under scrutiny. These numbers are not, of course, presented along with the court's opinion, and complaining works in particular are generally accessible only from the court's case docket or from the files of the attorneys involved. Unless, then, one somehow already knows the disputed works, one cannot read critically the court's published opinion. To do so, one needs to see the score of the musical work, and/or see and hear a recorded performance of it -- the latter increasingly important as audio engineering and performance style become ever more vital to the commercial success of popular numbers. This can be surprisingly difficult; while everyone has heard of Andrew Lloyd-Webber and can obtain the sheet music and recording of Phantom, who has heard of Ray Repp, and his Till You, that he claims Webber's work plagiarized? Even commercially successful works of popular music have fleeting appeal and brief shelf lives; within a decade or so of publication, the recording and sheet music of once-popular numbers can often be found only in specialized archives, or occasionally, tattered and shopworn, in the collections of municipal libraries.To improve access to this information -- access particularly helpful to legal scholars writing from a historical perspective on music copyright issues -- Columbia Law School's on-line archive will present audio and graphic representations of musical works that are, or have been, the subject of adjudicated music plagiarism cases. Text files summarize and comment upon the opinions in light of the musical works in each case, and contain the full text of the court's opinion. Image files provide representations of pertinent segments of the musical works in question through standard music notation; sound files include both MIDI (Musical Instrument Digital Interface) files with non-stylized renditions of the purely musical content of relevant portions of the disputed numbers, and also streaming audio clips (and video clips when relevant) taken from analog and digital recordings of performances that were intended for public delectation.We believe that this on-line archive will be useful to copyright academics, attorneys practicing in this area, and to musicians seeking insight into an entertaining albeit Cabalistic topic. The project's Discussion and Questions module suggests new means of accessing and analyzing information that pertains to an area of law that now begs inquiry into the issue of how changes in the creation, content, dissemination and consumption of popular music in America in the 20th Century -- which have not, for the most part, been acknowledged by the copyright bar -- should inform music copyright infringement judges and litigants, who tend to approach their work with the paradigms developed for disputes involving Tin Pan Alley numbers in the early decades of this century.