@Robert: Das kann ich dir erklären
Die Langversion, wenn du Englisch kannst, die Kurzversion, wenn nicht
Robert Galbraith isn't just a random pen name. Loosely translated it means "famous stranger."
"Robert" is derived from old Germanic, meaning "bright fame," and "Galbraith" is a Scottish clan (Rowling lives outside Edinburgh, Scotland) whose name comes from the ancient Gaelic word for "British foreigner."
Clearly, the title was a winking clue that slipped by most readers and journalists. As the British would say: "Cheeky fun, Jo. Cheeky."
(Quelle: http://www.hollywoodreporter.com/heat-vision/jk-rowlings-secret-novel-4-585240)
Kurzfassung: Robert Galbraith bedeutet so viel wie 'berühmter Fremder'.