Complex sentence: Indrek Hargla is a prolific writer of several kinds of sci-fi, fantasy and crime, whose reputation relies mainly on his Apothecary Melchior series, set in medieval Tallinn.
Split into simpler sentences: Indrek Hargla is a prolific writer of several kinds of genre fiction including sci-fi, fantasy and crime. His reputation relies mainly on his Apothecary Melchior series, set in medieval Tallinn.