The undisputed "King of Terriers," the Airedale Terrier is the largest and hardiest of the terriers, and an all around useful dog. The breed's coat is hard, dense and wiry, with a softer undercoat, and comes in both tan and black and tan and grizzle. This breed was one of the first used for police duty in Germany and Great Britain and has also been popular with Presidents, including Woodrow Wilson, Warren Harding and Calvin Coolidge.