12 books • 3 series
Book #1: Shadow of Doubt
Book #2: Beyond a Doubt
Book #3: Without a Doubt
Book #4: Room for Doubt
Book #5: Reason to Doubt
Book #1: The Navigator's Daughter
Book #2: Passport to Spy
Book #3: Murder on the Med
Book #1: The House on Hallowed Ground
Book #2: The House That Vanity Built