When buying the roast, look for it under several names: beef rib roast, standing rib roast or prime rib roast.
About 1 hour 30 minutes before beef is done, prepare and boil 8 medium potatoes as directed on page 589. For decorative potatoes, make crosswise cuts almost through whole potatoes to make thin slices and decrease boiling time to 10 minutes. Place potatoes in beef drippings in pan, turning to coat completely; or brush potatoes with melted butter and place on rack with beef. Continue cooking about 1 hour 15 minutes, turning potatoes once, until golden brown. Sprinkle with salt and pepper if desired.
With roast on carving board, carefully cut bone portion away from meat.
Turn roast bone side down. Cut slices evenly and toward bone side of roast.