Cut foil in pieces large enough to cover corn entirely, including some on the ends, enough to wrap the corn fully.
Shuck the corn, removing all silk. Place corn cob on a piece of foil. Spread butter on each cob, covering fully. Sprinkle all sides of each corn cob with salt & pepper (as desired). Wrap corn with foil and seal ends.
Place foil-wrapped corn on the barbecue and cook, turning every 5 minutes, for 15 minutes, or until cooked to your liking.*
*Corn can be cooked on the second rack, but it may take slightly longer.