Anna Barrows Shepley was born in Minneapolis, Minnesota, in 1857, the child of James C. and Mary Barrows Shepley. She studied art in New York under Harry Siddons Mowbray and in Paris at Académie Julian. After that, she established studios in New York and Connecticut, where she worked as a portrait painter and children's book illustrator. Two paintings were exhibited at the 1893 Chicago World's Fair and Exposition: "Work and Play" and "The Wonderful Story".

While living in Boston, Annie met and fell in love with Hyoso Omori, a Japanese man studying in the United States. On October 1, 1907, they were married quietly and within a year settled permanently in Tokyo. Here Hyoso, an educator interested in introducing American methods of physical training into children's education, pursued projects at various institutions, He also wrote articles, gave lectures, and was eventually employed by the government to oversee sport facilities in Tokyo.

Annie, who worked occasionally with her husband, established a fledgling settlement house, the Yurin En, in 1910 at Yodobashi, a poor suburb of Tokyo. The Yurin En's activities focused on young people's needs and included playgrounds, clubs, and classes. After the death of her husband in 1913, Annie chose to remain in Japan and continue the work that she and Hyoso had begun. It was not until 1935 that Annie retired from the Yurin En. In 1938 she was decorated by the government for her service to the country. Annie Omori's years in Japan were the source of inspiration for two books. One was a translation of medieval court ladies' diaries and the other was a history of the life of Prince Shotoku. Annie's last years were taken up by her family and her farm in Hirose. She died in Japan in 1943.

Charles Baldwin was the father of Mrs. O. E. (Bella) Williams to whom most of these letters were sent. He was also a friend of Annie's and in 1909, undertook a voyage to Japan to visit her. Born at Mount Vernon, Maine, in 1938, the son of Dexter and Lavinia Howard Baldwin, he came to Boston and grew prosperous in the meat-packing industry. A prominent member of the local business community, Mr. Baldwin was a charter member of the Boston Chamber of Commerce. In 1861, he married Esther Allen Cole, the sister of the artist Joseph Cole, with whom he had three children. He died in Winchester, Massachusetts, on October 13, 1927.