Complex sentence: The rising mystery writer disappeared from the publishing scene for 18 years, owing to the fact that, unlike Braun's light-hearted books, the popular mysteries had come to feature explicit sex, violence and foul language.
Split into simpler sentences: The rising mystery writer then disappeared from the publishing scene for 18 years. Unlike Braun's light-hearted series, popular detective fiction had come to feature explicit sex, violence and foul language.