Misc: Which organisation is the subject of Stephen Knights book The Brotherhood?

Questions

Music "Joy to the World" was a hit in 1971 for what band with three lead vocalists?

Music Besides "Auld Lang Syne" and "For He's a Jolly Good Fellow", what is the most frequently sung song in English?

Music Fifties rock "n" roll was revived by what greased hair, T-shirted, TV frequenting group?

Music Jerry Lee Lewis had Great ?

Music Name Jerry Garcia's long lived group.?