Complex sentence: Matus then turned to write a comprehensive book on the Shakespearean authorship question, which, though usually ignored by scholars, has a long history in public controversy and both amateurish and professional speculation, in Matus's view.
Split into simpler sentences: Matus then turned to write a comprehensive book on the Shakespearean authorship question. Though usually ignored by scholars, the authorship issue has a long history in public controversy and both amateurish and professional speculation, in Matus's view.