Brian looked closely at his father’s notes for further information, and was able to find an outline for a sequel to Chapterhouse: Dune, so began, with Kevin, to write two more books which complete the original series.
Hunters of Dune was released in 2006, and Sandworms of Dune was released in 2007.
The Heroes of Dune series then followed, which focused on the time periods between Frank’s original novels, which included Paul of Dune in 2008 and The Winds of Dune in 2009.
Two novels, The Thrones of Dune and Leto of Dune, were supposed to follow, but instead they were postponed to do another trilogy, which included Sisterhood of Dune in 2012 and Mentats of Dune in 2014.
source: express.co.uk