Once one of Germany's most notorious and hunted spies in America, Lothar Witzke and his numerous aliases have long been lost to the pages of history. With Agent of the Iron Cross, however, Bill Mills brings Witzke back into the spotlight. Written in a thoroughly engaging style, Mills' book details Witzke's sabotage and insurrection attempts in the United States beginning in 1915.

Thanks to the British blockade of the Central Powers at the beginning of World War I, the European allies had almost unfettered access to American armaments, much to the consternation of Germany. To staunch the flow of guns, ammunition, and other supplies to Britain, France, and Russia, Germany started a high-stakes campaign of sabotage across the United States. Starting in 1914, German officials at embassies and consulates attempted to disrupt shipments of Allied war supplies from America. Their efforts, while ingenious, were unable to stem the vast tide of goods from reaching Europe. They also caught the attention of US authorities resulting in several embassy officials being declared persona non grata and expelled from the country. Germany needed someone who could fly under the radar and, at least for a time, found him in Lothar Witzke.

In this meticulously researched work, Mills follows Lothar Witzke from his initial daring escape from internment in Chile on the ship Dresden to America where he hoped to be repatriated to Germany. Learning this was not possible, he chose to serve the Fatherland in other ways, initially as a courier of confidential information for the German embassy and, later, as a saboteur and assassin.

Together with Kurt Jahnke, a naturalized American of German extraction, he embarked on a series of sabotage missions. Because of the two men's skillful execution, most sabotage attempts were assumed to be accidents, and the full extent of Witzke and Jahnke's activities will probably never be known. Witzke did admit they had participated in three of the most destructive incidents: the S.S. Minnesota, the Black Tom munition depot, and the Mare Island Naval Station. The first two of these operations took place before America became a combatant.

Immediately after the United States entered the war, there was a mass exodus of German agents to Mexico. Witzke and Jahnke set up a new base of operations in Mexico City, where Jahnke became a spymaster, building a network of fifteen to twenty agents located throughout the Western Hemisphere. The United States sent various agents south to infiltrate the German's operation, albeit with mixed results. Some agents were identified immediately by the Germans, who then used them to send disinformation back to the States, while others managed to gain access to a deeper inner circle.

One of the most audacious operations the Germans planned was a joint German-Mexican invasion of the United States to coordinate with the spring offensive in Europe. As a prelude, Jahnke sent Witzke into America on a three-pronged mission to: incite African Americans into insurrection and murder in the South, destroy munitions plants and food stores using Industrial Workers of the World (IWW) agents, and assassinate the American intelligence officer, Byron Butcher. Mills takes pains to explain that these were not such far-fetched fantasies as they might be viewed as today but instead grounded in the socio-economic realities of 1917–1918. Certainly, racial tensions were high and the Germans wished to exploit them. Unfortunately for the Germans, the two men tasked to help Witzke carry out these nefarious plans—William “Guillermo” Gleaves and Dr. Paul Altendorf were both Allied agents. Forewarned and thus forearmed, the US authorities were able to foil the German plan.

After apprehending Witzke on US soil, American agents had trouble proving he was a spy because he carried nothing incriminating on him. US agents had to raid his hotel room across the border to seize his cipher key and coded messages. Even with the key, however, the American could not read the messages. Mills provides an excellent chapter on how the cipher was finally broken by two professors from the University of Chicago.

Lothar Witzke was found guilty and sentenced to death for spying, but he managed to escape the hangman's noose. While the case was awaiting judicial review, World War I ended. The review board upheld the conviction but recommended commuting his sentence to life confinement at hard labor. The recommendation was confirmed by President Woodrow Wilson in May of 1920. Under diplomatic pressure, President Calvin Coolidge pardoned Witzke in November 1923 with the understanding that he leave the United States and never return.

The cat-and-mouse game German agents and American authorities played during World War I is riveting but often overlooked. From Black Tom Terminal in New York to Mare Island in California, Witzke conducted a campaign of sabotage and espionage that has slid from the American mind. Mills' account puts it back in the public consciousness with flair and readability.