It speaks to the particular kind of high-profile musical experimentalism that thrived in that era, at least in some quarters — or, rather, in some studios. In this case, the Grappelli and the Floyd boys found themselves recording in adjacent ones. Why would the latter invite the former, already an elder statesman of jazz and a collaborator with the likes of Django Reinhardt, to sit in on a session? (Watch Django and Grappelli play together in the 1938 film, Jazz Hot here.) Well… why not? They needed something impressive to follow Dark Side of the Moon, after all.