Two weeks before the U.S. entered World War I, a Chicago advertising executive visited the Department of Justice with a proposal - organize the country's businessmen into a secret force of volunteer agents to ferret out and investigate enemy activities within the United States. The country, overcome by a wave of patriotic fervor, had also become gripped with fear and uncertainty of the influx of immigrants from the very countries with which the country was now at war. The idea received quick approval and caught on like wildfire. Soon thousands of volunteers in every major industry, trade and profession were on the alert nationwide, maintaining surveillance and investigating cases for the Department of Justice Bureau of Investigation. They would grow to become 250,000 strong. Written as a real-life adventure story, The League reveals how the organization began, the manner in which it operated, and the varied missions that it performed on behalf of the U.S. government. It is an extraordinary chapter in American history, when almost any citizen could receive official credentials as a volunteer investigator. From a running gun battle on the streets of Philadelphia, to the seizure of a disguised German commerce raider on the high seas, to the hunt for the radical bomber that attacked the Federal Building in Chicago, The League is a fascinating true story that will not soon be forgotten.