Hester Latterly is a main character of Anne Perry's Monk detective series.
She is a nurse by trade who served with Florence Nightingale in the Crimea.
Her inquisitive nature eventually allows her to help Monk in his investigations, despite annoying him at first.
[1] After trying to work in a free hospital, she is fired for insubordination and takes to private nursing clients.
After this, with the help of her friend Callandra Daviot, she opens a clinic for injured and sick prostitutes in the Central London slums.