Series 8, Markoosha Fischer Papers, 1931-1977, is arranged in three subseries: Correspondence (arranged alphabetically), Writings (arranged alphabetically), and Personal Materials (arranged chronologically), which document her life in Europe as well as her time in the United States. The correspondence does not include letters with her husband and sons, which can be found in Series 9, Family Papers. Some of the general correspondence is in German or Russian, including that with Nikolai Troitsky (Boris Yakovlev), director of the Russian Library in Munich and subeditor for the book Thirteen Who Fled (1949). Another correspondent writing in Russian is Joseph A. Rosen, for whom Markoosha worked for one year in a new Jewish settlement in the Ukraine, before settling in Moscow in 1928.

There is some correspondence with Eleanor Roosevelt, through whose intervention Markoosha and her sons were able to leave the Soviet Union. Correspondence of Paul and Hede Massing, friends from Berlin and Moscow who moved to the United States in the 1930s, is also present. George and Victor Fischer stayed with the Massings for one-and-a-half years (1931-1933), and their letters in Series 9, Family Papers, complement those found here. During the McCarthy era, Hede Massing was convicted of spying for Moscow.

Of particular interest is the correspondence from the Wloch and Wolf families, other German communists who had moved to Moscow during the Nazi regime. Elsa Wolf was Markoosha's best friend in Moscow. Erna Wloch and her children, Lothar and Margot, disappeared in 1942 after the news that her husband, a victim of the Stalin purges of 1937, had died. However, both families turned up in Berlin after the war, and their correspondence covers the immediate post-war period. Erna Wloch, who died in 1946, wrote Markoosha about mutual women acquaintances and their fates under the Nazi regime. The Wolf and Wloch correspondence contains many references to and letters from the boys, Lothar Wloch and Konrad ("Koni") and Markus ("Mischa") Wolf, who were good friends with Markoosha's sons. By 1980, Konrad, who had become a respected filmmaker and head of the Academy of Arts in East Germany, was planning a film about their boyhood friendship, but died before he could complete it. His brother Markus ("Mischa") Wolf, chief of the East German foreign intelligence service, finally wrote a book on the topic: The Troika (1989).

There is disappointingly little correspondence from Markoosha's Menshevik sister Theresa Rubinstein, who served as secretary of a Russian socialist group in Germany before the First World War and with whom Markoosha lived prior to the war. (They also lived together in Copenhagen during the war.) Theresa later moved to New York. Nina Rubinstein, her daughter, was very close to Markoosha in her later years.

The Writings subseries contains material relating to Markoosha's own books, which were based on her experiences in the Soviet Union and in Germany (where she worked for the International Rescue and Relief Committee (IRRC) between 1948 and 1951). Her unpublished manuscripts contain three chapters excluded from her My Lives in Russia. The first two describe her childhood in Lithuania, her youth in a Swiss "finishing school," her time at Lausanne University, and the years afterwards, when she lived with her sister, Theresa. Of particular interest are her anecdotes concerning the Russian revolutionary exiles she met in this period, including Karl Radek, Alexandra Kollontai, Yuri Larin, and Maxim Gorki. Her third chapter, covering the period 1916-1922, contains a full account of her experiences as a secretary and translator at the 1922 Genoa Conference, with a description of all the Russian officials she met. In addition to these early chapters, there is an account of the period from July 1938 to January 1939, originally intended to be published as a sequel to My Lives in Russia. In it, Markoosha describes the Soviet secret police's attempts to recruit her after she had applied for a visa to the United States.

The unpublished manuscripts also contain drafts and notes for a third novel, Anya. Her first novel, The Nazarovs (1948), described four generations of a Russian family between 1892 and 1942 and the perspective of each family member on that time span. The Right to Love (1956), dealt with three love affairs in the post-war ruins of Berlin. In Anya, Markoosha addressed the Jewish question in the Soviet Union. For all four books, including her last, Reunion in Moscow (1962), there is a file with correspondence from the publisher (Harper's), readers and friends, and book reviews (many from scrapbooks).

The Personal Materials subseries contains memorabilia, clippings and publicity (mainly for Markoosha's lecture series), financial records and correspondence (mainly royalty statements) and appointment and address books. Among the memorabilia is a typescript copy of poems by Boris Pasternak.