Humans and dogs have shared a close relationship for thousands of years. Today, there are around 600 million domestic dogs living throughout the world. Many of them are trained to perform important tasks. These working dogs pull sleds, assist the disabled, protect us from harm, and search for lost people. They work alongside farmers, soldiers, and hunters. Readers will discover how working dogs are bred and trained and how these hardworking canines find happy homes when it comes time to retire.