Clodagh Finn: Time to celebrate the first Irishwoman to sell books by the million

Cork-born Ethel Lilian Voynich (nee Boole), daughter of George Boole., was a publishing sensation.
Here’s a great quiz question; no sneaky Googling now. Who was the first female Irish writer to sell books by the million?
Double points to anyone who answers Ethel Lilian Boole, author of the international bestseller
. She was born in Cork, even if the city doesn’t make enough of that glorious connection.