Mildred Elizabeth Harnack (née Fish; September 16, 1902 – February 16, 1943) was an American literary historian, translator, and member of the German resistance against the Nazi regime.

Like numerous groups in other parts of the world, the undercover political factions led by Harnack and Schulze-Boysen later developed into an espionage network that collaborated with Soviet intelligence to defeat Hitler.

She stayed at a rooming house popular with journalists and writers, but left after facing some mild prejudice, which caused her to change her major from journalism to humanities, then later to English literature.

[8] After a brief love affair, they were engaged on June 6, 1926, and wed on August 7, 1926[9] in a ceremony at her brother's farm near the village of Brooklyn, Wisconsin.

[20] By the time Fish-Harnack arrived in Giessen, more than half the student population were vocal in their support of the Nazis[21] and therefore opponents of several faculty members.

[21] On February 1, 1931, Mildred Harnack began studying at the University of Berlin on a fellowship from the Alexander von Humboldt Foundation.

[23] She taught courses on Emerson, Whitman, Theodore Dreiser, Sinclair Lewis, Thomas Hardy, and George Bernard Shaw.

[29] They became interested in the Soviet Union and communism, seeing them as a solution to the rampant poverty and unemployment that Germany suffered during the Great Depression.

[33] At the time, the German Americanist and ardent Nazi Friedrich Schönemann[34] had returned from leave in America to work in the English department.

[37] Mildred hoped to go, but due to a scheduling conflict decided to make her own way there by booking the trip using Intourist and flying back early.

[37] Fish-Harnack's career as a scholar was saved when a family friend who was also president of American Student Union, Warren Tomlinson, suggested she take over his position as lecturer at the Berlin municipal evening high school.

She socialised with her students and discussed economic and political ideas from the United States and the Soviet Union in an open and frank manner.

[43] Fish-Harnack, seeking additional income, launched a lecture series that was held in Klaus and Emmi Bonhoeffer's home.

[44] Dodd became Fish-Harnack's friend in Berlin,[45][46] and her manuscript, In Memory, found in her Prague apartment attic in 1957, stated:The years of our acquaintance were the most significant of my life.

[45] In a letter Fish-Harnack wrote to her mother in October 1935, she described Dodd as a talented writer of literary criticism and short stories with "a real desire to understand the wider world...

[47] The Harnacks began to host a Saturday literary salon on Hasenheide where political views among editors, publishers, and authors were freely expressed;[36] the attendees included publishers Samuel Fischer, Ernst Rowohlt, and Rowohlt's son Heinrich Marie Ledig-Rowohlt; translator Franz Frein; physician and writer Max Mohr; authors and playwrights Adam Kuckhoff, Max Tau, Otto Zoff, and Ernst von Salomon; journalist Margret Boveri; critic Erich Franzen; and Mildred's students, such as writer Friedrich Schlösinger.

[36] In Dodd's book Through Embassy Eyes, she mentioned a report by an American publisher who had visited the Fish-Harnacks in 1934, who stated:He was expecting a lively exchange of views and engaging conversations that evening—definitely more appealing than that to which we were used in diplomatic circles.

[60] After 1935, Fish-Harnack did not publish any literary criticisms, essays, or newspaper articles, as the increasing presence of the Nazi regime made any writings a "rubber stamp for official views".

[61] In 1936, her German translation of Irving Stone's biography of Vincent van Gogh, Lust for Life, was published.

[63] Leiser found Fish-Harnack changed, from the open and trusting person she had known into someone who seemed distant and superior, a side-effect of the deceit necessary to hide her true feelings in Germany.

"The development of contemporary American literature in some of the main representatives of the novel and the short story"), and was awarded her doctorate at the University of Giessen on November 20, 1941.

[71] In 1941 she was hired as an English-language professor at the Foreign Studies Department of the Friedrich Wilhelm University, which was run by SS Major Franz Six.

[74] Harnack lent books to the potential recruit as a test of their intellect, as there was little chance of winning such people over if they did not understand politics.

The most important of these was a group run by Harro Schulze-Boysen, a Luftwaffe lieutenant and descendant of an old German military family who had known Harnack since 1935,[79] but was reintroduced to him sometime in late 1939 or early 1940 through Greta Kuckhoff;[80] the Kuckhoffs had known the Schulz-Boysens since 1938 and started to engage them socially in late 1939 or early 1940 by bringing Fish-Harnack and Libertas Schulze-Boysen together while on holiday in Saxony.

The initial meeting of the women gave rise to a licentious image of the group that persisted for decades after the war, based primarily on Gestapo and Abwehr reports.

[83][84] However, industrialist Hugo Buschmann, who was an informant and Harro's close friend, stated that the group lived dangerously, but there was no evidence for Perrault's conclusion.

[90] When Wilhelm Vauck, principal cryptographer of the Funkabwehr,[91] received the ciphers from Wenzel, he was able to decipher some of the older messages.

[98] Arvid's brother Falk Harnack, also a resistance fighter, was able to escape and survived the Second World War as an ELAS partisan in Greece.

[100] While newspapers learned about the execution shortly after the war, the U.S. government concealed additional information about Harnack's story.

However, while investigators described her actions as "laudable", they concluded that Harnack's execution was technically not in violation of international law since she was a spy and had received a trial.