Book excerpt: Nat, Nat, the Nantucket Cat, walked one sunny day Down a nice Nantucket street, his own Nantucket way. "What a very pretty morning," he purred so happily. "A pretty morning on our pretty island in the sea." On special days like this, he thought, there's just one thing to do! Grab your towel and sunglasses, and call a friend or two, And meet them on your favorite beach in wonderful Nantucket- And don't forget the sun tan cream, your shovel and your bucket!