I picked up a few books by Terry Brooks and I was just wondering how you're suppose to read them.

Inside the book it says all the books he wrote and it says in one group "Shannara" and I have all the books under that.
But THEN it says "The Heritage of Shannara" and "The Voyage of the Jerle Shannara"
Are all the books part of the same series with the same characters or what? Or are they each a new group about something a little different with new characters?