•Why it earns a slot
Agnes Grey is the earliest sustained first-person account of the governess's experience in Victorian fiction, and its unflinching detail of institutional powerlessness, class condescension, and the difficulty of moral action without authority gives it a documentary force that distinguishes it from the romantic governess narratives that followed.
Agnes Grey, a sheltered clergyman's daughter, takes work as a governess to help her impoverished family and endures two bruising placements: first with the cruel, ungovernable Bloomfield children, then with the vain, indulged Murray daughters at Horton Lodge. Through years of loneliness, professional humiliation, and unrequited longing, she quietly falls in love with the principled curate Edward Weston, and after her father's death and the founding of a small school with her mother, she and Weston meet again by chance on the seashore and marry.
This distillation is written from the freely available original, which is always the better read when you have the time: gutenberg.org.