I read about this on someone's blog and wanted to read it, so happily managed to get it via BookMooch. I've been reading it this week in France and found it very absorbing. It is the story of Elizabeth Wilson, who was the maid to Elizabeth Barrett -- she worked as EB's lady's maid in Wimpole Street for a couple of years before the elopement with Browning, and then was privy to the wedding, and accompanied the couple when they went off to live in Italy, where she became the adored nursemaid of their son Pen. After some years there she married an Italian and had two children -- the first of whom she had to leave with her sister, as the Brownings would not let her keep him with her. She later left EBB's service to run a boarding house, but stayed close to the family, for whom her husband also worked, until EBB's death.
This is the bare bones of the story, all of which is true (taken from EBB's and RB's letters). But Margaret Forster has wonderfully imagined this young woman's inner life. It is rather a sad story, as she adored her mistress and thought for a long time that they had broken through the mistress/servant barrier and become real friends, only to find this was not in fact the case. It has made me long to read Forster's biography of EBB which I shall seek out forthwith.