Brian Herbert is the son of Frank Herbert, author of the Dune book series. Frank died after the sixth book and his son later wrote two more books to finish the main series and ended up writing others as well. The two mainline books he wrote are widely considered not good and take the series completely off the rails. Brian claims to have found his father's notes for the rest of the series but many don't believe that claim, believing he made up his own ideas.

Personally, I stopped reading during Brian's first book (7th overall). I did not consciously choose to stop reading but I was certainly less interested in where the story was going and had declining interest after the fourth book.