Zhaohao Wu (pinyin: Wu, Zhaohao, Wu, Zhaogao; Wade Giles: Wu, Chao-hao; traditional Chinese: 武兆鎬; simplified Chinese: 武兆镐; also known as D. H. Wu, Peter Petrashevskaya; Wu, Chan-han, Wu, Juexian, 吳覺先, 吴觉先; and Wu, Jianxi, 武劍西, 武剑西) was born in Gongyi, Henan province, 1899. He attended Henan Overseas Preparatory School (later known as Henan University) in 1913, with a concentration in German. In 1918, he studied civil engineering at the Shanghai Tongji Medical and Engineering College (later known as Tongji University). With sponsorship from the Henan Department of Education, he began studying mathematics and philosophy in Germany at the University of Göttingen in 1923. During his time in Germany, he was exposed to European literature and Marxism and later became zealous in the worldwide Communist movement. In 1925, he departed for Moscow and studied at the Sun Yat-sen University. He later worked for the Comintern in Moscow and he was also a member of the Sixth National Congress of the Chinese Communist Party held in Moscow, 1928.

Zhaohao Wu met Irene Petrashevskaya (1908-?) in 1924 while he was studying abroad in Germany. Irene was a member of the Red Women and Girls' League in Weimar Germany. While he was in Moscow, he introduced Irene Petrashevskaya as his companion in his letters to his younger brother, Zhaofa Wu, who was at the time studying biology in the U.S. at the University of Wisconsin-Madison. In 1927, Irene began her study at Moscow Sun Yat-Sen University with Zhaohao and later also worked for the Comintern. Zhaohao Wu returned to China in 1929 and began working at the Comintern's newly established Far East Division in Shanghai the very next year. In 1935, he mobilized a mass student protest against Japanese aggression in Beiping, which was known as the December 9th Movement. After 1940, he became a professor at the Northeastern University in China, Wuhan University, and later the Deputy Director of the Ministry of Higher Education, the Editor-in-Chief of the Commercial Press, the High Education Press, and the first President and the Editor-in-Chief of the People's Education Press. He was also the first to translate many socialist philosophical works from German into Chinese.

Zhaohao Wu's younger brother, Zhaofa Wu (pinyin: Wu, Zhaofa; Wade Giles: Wu, Chao-fa, Wu, C.F.; traditional Chinese: 武兆發; simplified Chinese: 武兆发; courtesy name: Jixu, 季許), is the recipient of the letters in this collection. Zhaofa was born in 1904. He attended Henan Overseas Preparatory School in 1917, with a concentration in English. Like his brother, he received sponsorship from the Henan Department of Education and studied biology at the University of Wisconsin-Madison in 1923 and received his doctoral degree in 1929. After he returned to China, he was a biology Professor at various universities in China. He was also the Editor-in-Chief of the Chinese Journal of Biology. During the Anti-Rightist Campaign in 1957, he was falsely classified as a "rightist" and was publicly persecuted and humiliated to the point of committing suicide.