Revisiting one of rock’s most celebrated albums is daunting. But when Van Morrison played his 1968 classic Astral Weeks in its entirety for its 40th anniversary, he proved both the album’s enduring worth and his continuing vitality as a performer. Van composed the song cycle’s magical mix of folk, rock, jazz and blues with a young man’s sense of wonder. But here he shows the gravitas of an artist in full maturity, commanding the music’s freewheeling flow with even greater authority and showing just as much vocal agility as ever.