This is a notebook belonging to Romaine Brooks, whose papers are kept in the Archives of American Art and were digitized in 2012. The notebook contained is from the 1950s and “contains lists and Romaine’s thoughts.”

I’ve always loved her paintings for their stark look and interesting female subjects, such as this one:

See more at Summary of the Romaine Brooks papers, 1910-1973 – Digitized Collection | Archives of American Art, Smithsonian Institution.