Writings for young adults were a significant part of Silverberg's production in the 1960s, but faded away for a time while he concentrated on complex adult themes. In the 1980s he returned to writing for young adults, mostly science fiction or nonfiction, not fantasy like "As Is," with the notable exception of the Majipoor Chronicles, a collection of short stories of heroic fantasy set on the world of Majipoor, where the Lord Valentine novels are set, beginning with Lord Valentine's Castle (1980). The Valentine novels tend to be very atmospheric with slow-moving plots.