The first three books, Sword of Shannara, Elfstones of Shannara, and Wishsong of Shannara follow Shea and Flick Ohmsford and their immediate descendants. The first book has been criticized for overly borrowing themes from J. R. R. Tolkien's The Lord of the Rings.
The next four books known as the Heritage of Shannara are set 300 years after the first book. These follow three of Shea's descendants Walker, Coll and Par.
The most recent series The Voyage of Jerle Shannara is set around the life of Jerle Shannara.
The prequel First King of Shannara is set during the lifetime of Jerle Shannara, an ancestor of Shea.
The relationships can be seen in the Shannara Family Tree.