When his mother suggests he ``go build something,'' Armstrong constructs a ladder to the clouds, and as the numbered clouds pass bysix, seven, eighthe lassos the ninth as his personal refuge in the sky. Cloud Nine is not only a place of refuge, where Armstrong can escape from his boisterous family, it's also a bed, a trampoline, and a vehicle. Despite pleas and messages from his family, sent via the mailman, planes, and mountain climbers, Armstrong refuses to come down. Familial guilt, refreshingly, just isn't strong enough to make Armstrong abandon his aerial adventures. It's only when his cloud gets snagged on a sharp mountain peak, that Armstrong is forced to land; his family rushes to welcome him back into the noisy fold. Anyone who's ever cloud-gazed or flown through a bank of clouds in an airplane will identify with Silver's fantasy of escaping into the sky, to take refuge from earth's clutter. Ormerod's paintings extend the fantasy element effortlessly, often through wordless panels. Science may not allow humans to float on clouds like inner tubes, or sky surf on a jet-powered cumulus, but this book's paean to the imagination will transport readers easily, believably, up to Armstong's cottony retreat. (Picture book. 5-8)