Morrison's songs are an instinctive, organic mixture of Celtic folk, blues, and jazz. Producer Lewis Merenstein added chamber orchestrations later and divided the album into halves: 'In The Beginning' and 'Afterwards' with four tunes under each heading. Van Morrison plays acoustic guitar and sings in his elastic, bluesy, soulful voice, accompanied by crack group of jazz studio players: guitarist Jay Berliner, upright bassist Richard Davis, Modern Jazz Quartet drummer Connie Kay, vibraphonist Warren Smith and soprano saxophonist John Payne (also credited on flute, though that's debatable - some claim an anonymous flutist provided those parts). Astral Weeks is generally considered one of the best albums in pop music history, but for all that renown, it is anything but an archetypal rock & roll album.