136 books • 45 series
Book #1: Noughts and Crosses
Book #2: Knife Edge
Book #3: Checkmate
Book #4: Double Cross
Book #5: Crossfire
Book #1: Secret of the Terrible Hand
Book #2: Peril on Planet Pelia
Book #3: Mellion Moon Mystery
Book #1: The Secret Of The Terrib
Book #2: Peril On Planet Pellia
Book #4: Quasar Quartz Quest