Rachel Sassoon Beer was the first woman to edit a national newspaper when she simultaneously owned and edited both The Observer and The Sunday Times in England in the 1890s. Born to the illustrious Sassoon family in Bombay, she was the only daughter of Sassoon David Sassoon (1832–1867), who was the third son of David Sassoon (1792–1864). Rachel’s mother Farha, later known as Flora (1835–1919), was the daughter of Solomon Reuben of Baghdad. The first of the Sassoon brothers to settle in England, S. D. Sassoon moved to London in 1858 shortly after Rachel’s birth. His family followed soon after. Rachel’s father was very active in Anglo-Jewish communal life. In 1863 he bought an estate at Ashley Park in Surrey. He died suddenly at the age of 35 in 1867, leaving his wife to bring up Rachel and her three brothers: Joseph (1855–1918), Alfred Ezra (1861–1895), and Frederick Meyer (1863–1889).

Together with her brothers, Rachel was educated privately, first by visiting tutors and then by a resident one. She worked for two years as an unpaid hospital nurse at the Brompton hospital in London and then remained in London. In 1887, at the age of 29, she married Frederick Arthur Beer, son of a London financier, Julius Beer, originally from Frankfurt. Rachel was the second member of her family to intermarry, following after her brother Alfred Ezra Sassoon (father of the poet Siegfried Sassoon), to the great disapproval of her mother. The wedding took place at the Holy Trinity Church in Sloane Street. Among the guests were Prime Minister and Mrs. Gladstone.

In 1870 Julius Beer had bought the oldest Sunday paper in England, The Observer (founded in 1791), which he passed on to Frederick, who, himself not physically strong, in turn involved his wife in operating the publication of the paper. A pioneer newspaper editor and manager, Rachel began to submit first letters and later articles to The Observer, before becoming assistant editor and subsequently editor of the paper. In 1893 she acquired The Sunday Times (founded in 1821), and continued to run both newspapers with varying degrees of supervision and involvement until 1903.

Rachel Beer was a member of the Institute of Journalists and of the Institute of Women Journalists. In 1898 she personally obtained a confession from Ferdinand Esterhazy, the French major (and German agent) who had forged the document setting out the military secrets that Captain Alfred Dreyfus had allegedly passed on to the Germans. This had been the basis of the case against Dreyfus in what became known as the Dreyfus Affair. Rachel Beer published successive articles relating to Esterhazy, which led to calls for a retrial for Dreyfus. However, Esterhazy then retracted his confession and sued the Observer for libel. Rachel refused to back down. In 1899 Esterhazy admitted his lies and Dreyfus was released. This was considered to be largely due to Rachel Beer’s persistence and she was much admired by her fellow journalists. In general, however, both newspapers declined in circulation under her editorship.

Rachel continued to devote attention to the condition of the nursing profession. She was very interested in music, composing and publishing pieces of her own. Her husband, who may have suffered from syphilis, became paralyzed and mentally ill, and Rachel nursed him devotedly. When Frederick Beer died in 1903 she inherited the whole of his considerable estate. Unfortunately she herself became ill almost immediately: family sources suggest that she had contracted syphilis from her husband. She was certified as insane and placed in the care of the Commissioners of Lunacy in 1904. Her brother Joseph was appointed to act as administrator. She spent the rest of her life in a country home in Tunbridge Wells with full nursing care and an extensive staff, surrounded by her remarkable art collection. She died in 1927, having outlived all her siblings. Her funeral took place in the borough cemetery and was conducted by a Church of England vicar. Her large estate passed to her surviving nephews, niece and great-niece. Her nephew Siegfried Sassoon was said to have lived comfortably from his share of the proceeds. He came to acquire a portrait of Rachel which had been purchased at auction after her death by one of her nurses, and it was hung in a place of honor in his library.