The site Well-Mannered Frivolity points us to Unesco's magnificently named Index Translationum, which attempts to catalog all books in translation everywhere (or at least among its hundred-odd member states), a Borghesian task.
Our own Georges Simenon comes in at #16 on the list of most translated writers, with 1,959 translated books to his name. He's right after Isaac Asimov and just before Pope John Paul II. The index is worth looking at, and the Translationum database could proove be a very useful resource, indeed.
As Ms. Well-Mannered Frivolity comments, "Authors who write prolifically have a distinct advantage here," which explains why Barbara Cartland outranks the New Testament.
The photograph above shows M. Simenon (for once without his pipe) adding another volume to his "all-Simenon" bookshelf.