Lord Prestimion by Robert Silverberg
The latest volume in the bestselling fantasy saga that began with Lord Valentine's Castle: the eagerly awaited new novel in the Majipoor sequence, one of the most famous and fully realized worlds of modern fantasy.
A sequel to THE SORCERERS OF MAJIPOOR, this sumptuous fantasy is set in a world with four moons in the sky, a Desert of Stolen Dreams, a deadly Labyrinth which is the Register of Souls, rootless trees, flesh-eating flowers... Prestimion has won his title in a lengthy civil war.
Now Coronal of Majipoor, Prestimion's first mistake is to use a sorcerer's device to obliterate the war universally from memory. Majipoor must be seen as the perfect world. The result is mass psychosis. Thanks to his mother's worldwide control of minds from the Isle of Sleep and the allegiance of clever Prince Dekkeret, Prestimion will defeat his resurgent enemy Sambail and cure his people... but only just.