He is known for studies of the history of the Chinese book, Chinese bibliography, paleography, and science and technology, especially the history of paper and printing in China, notably Paper and Printing, Volume 5 Pt 1 of British biochemist and sinologist Joseph Needham's Science and Civilisation in China.

[1][2] He is also known for risking his life to smuggle tens of thousands of rare books outside of Japanese-occupied China during World War II.

[3] Tsien was born on January 11, 1910[4][a] in Taixian (modern Taizhou), Jiangsu Province, to a prominent family that descended from King Qian Liu, founder of the Wuyue kingdom.

Due to their political activities, Tsien and his colleagues were arrested by the Jiangsu warlord Sun Chuanfang.

[5] In 1927, he enlisted in the army to take part in the Northern Expedition's military campaign to unite China under the Nationalist government.

In early 1937, the National Library transferred him to the Shanghai branch to curate a large group of rare books and manuscripts which the government had sent there in 1931 when the Japanese army had invaded Manchuria.

In order to evade Japanese confiscation, he marked them as new books and waited to ship them in small groups at times when he knew a friendly Chinese customs worker was on duty.

In the mid-1960s, the United States gave the books to Taiwan, where the Republic of China government had retreated after losing the civil war.

[12] In his nineties Tsien helped with the revision and proofreading for the 2nd edition of his Written on Bamboo and Silk, which appeared in 2004, and arranged for it to be translated into Chinese.

Tsien's nephew, Xiaowen Qian, is an assistant to the curator for the East Asian Collection of University of Chicago.