Brian Herbert and Kevin Anderson have written some 10+ DUNE books (Who do they think they are, Christopher Tolkien [MORE STUFF I FOUND WEDGED BEHIND MY DAD'S DESK DRAWERS, VOLUME 12]?).
Six prequels (HOUSE ATREIDES, HOUSE HARKONNEN, HOUSE CORRINO, THE BUTLERIAN JIHAD, THE MACHINE CRUSADE, THE BATTLE OF CORRIN), two sequels (HUNTERS OF DUNE and SANDWORMS OF DUNE), a miscellanious (THE ROAD TO DUNE), and now PAUL OF DUNE, the first of four set in-between the original DUNE books (to be followed by JESSICA OF DUNE, IRULAN OF DUNE, and LETO OF DUNE).
Are they milking it? Probably. I listened to a few of the "War of the Thinking Machines" trilogy (THE BUTLERIAN JIHAD, THE MACHINE CRUSADE) as books-on-CD from the library, and they weren't bad. Kind of like the new BATTLESTAR GALACTICA, actually. I don't know that I buy that 10,000 years before DUNE, the same family names (Atreides, Harkonnen, etc.) were all the key players in the galaxy.
I don't think the books are much like what Frank Herbert would have written, but on the other hand, Frank Herbert wrote three good DUNE books and then three almost unreadable ones.
Certainly the son of the author teamed up with an author with a proven track record for playing in other people's universes seems a good plan. The Duneiverse (I was kind of hoping I'd just coined that word, but a little googling has of course shown otherwise) is interesting enough to have some more tales from it.
I haven't read the two "sequel" novels. One time at DragonCon I saw Brian Herbert and Kevin J. Anderson give a Q&A, and at that point they said they'd found a disk in a box in Frank Herbert's garage with DUNE VII written on it, which gave the outline.
Now they say they found it in a bank vault.
Both tales can't be true. Well, unless the disk in the box in the garage gave a fiendish series of Da Vinci Code clues which eventually revealed the whereabouts of a key to a safety deposit box....
Not that I'm knocking a little literary window-dressing for versimilitude. If it worked for S. Morgenstern...
In any event, now they're writing in-between DUNE novels, this first one, PAUL OF DUNE, takes place between DUNE and DUNE MESSIAH.
As a reader, this maybe is more in a comfort zone; it's not set in the distant past of DUNE, it's not set in a future where the events seem weirder and weirder and un-DUNE-ish, it's filling in the cracks in the original novels.
Uneasy is the head that wears the crown, and Paul is seeing his Jihad get out of control. And we have flashbacks to his boyhood, during a War of Assassins.
It's an entertaining read. Only problem with the book is a shortage of sandworms. In truth, I'd probably like a book called SANDWORMS! SANDWORMS! SANDWORMS!, because sandworms are cool!