“The releases are a response to a new European Union copyright law that will extend copyright protection to 70 years — but only for recordings that were published within 50 years after they were made. So in the case of the Beatles, the group’s 1963 debut album, “Please Please Me,” already benefits from the copyright extension, but the unreleased session tapes — unused versions of the same songs on the album — did not, hence the release. Similarly, the BBC performances released on “Live at the BBC” (1994) and “On Air — Live at the BBC, Vol. 2” (2013) — are protected, but they represent less than half of the 275 performances the Beatles recorded for the BBC between 1962 and 1965. Another 44 of those recordings are included in the set to be released on Tuesday.”

– http://app.nytimes.com/#2013/12/12/arts/european-copyright-laws-lead-to-rare-music-releases