Norbert Pearlroth is famous for being the head researcher for Ripley's Believe It or Not, but he also wrote a column on Jewish Surnames, and when he was asked about the surname "Deifik", he wrote (in an article published in 1946):
This is a very unusual name. I encountered it in a novel many years ago, but I never thought I'd find it in real life.
Does anybody know which novel he was referring to? Bear in mind that Pearlroth was reputed to be fluent in 14 languages, so the novel in question need not necessarily have been written in English, Russian, or Polish.
