One of the greatest soprano legends of all time, Nilsson's 1963 Decca recital with Sir Edward Downes of popular opera arias by Wagner, Weber, Beethoven, et.al. has never been fully issued. Here it is on CD - issued complete for the first time and in the fabled sumptuous Decca sound - coupled with her rare "Ah, perfido" (issued only on a 45rpm record) as well as four beautiful Christmas songs.    Artists: Birgit Nilsson (soprano), Ake Leven (organ).  Composers: Adam, Beethoven, Franck, Gounod, Gruber, Wagner, Weber.  Conductors: Sir Edward Downes.  Orchestras: Orchestra of the Royal Opera House Covent Garden.