Emily Dickinson
She published almost nothing in her lifetime. She changed American poetry forever anyway.
Emily Dickinson wrote nearly 1,800 poems from the relative seclusion of her home in Amherst, Massachusetts — and most of them weren't discovered until after her death. She wrote about death, immortality, nature, love, and the interior life with a compression and strangeness that her era wasn't ready for. We are still catching up.
Her lines arrive in flashes. A single image that opens into something enormous. A dash that carries more weight than a full stop. She had no interest in saying things the expected way, which is exactly why her words stay with you long after other poets have faded.
Dickinson wrote for the person alone in a room with too many thoughts and not enough language for them — and then she gave them the language. If her work finds you, it tends to find you at exactly the right moment.