Complex sentence: The first two novels were written by, but they were slow paced so another author was brough in with later stories being published under a house name, Grant Stockbridge; most of the Spider novels were written by Norvell Page.
Split into simpler sentences: The first two novels were written by but they were slow paced so another author was drafted in with later stories were published under a house name, Grant Stockbridge. Most of the Spider novels were written by Norvell Page.