The Mystery of the Strange Messages: Book 14

The Mystery of the Strange Bundle: Book 10

The Mystery of the Vanished Prince: Book 9

The Mystery of Holly Lane: Book 11

The Mystery of the Missing Man: Book 13

The Mystery of Tally-Ho Cottage: Book 12

The Mystery of the Pantomime Cat: Book 7

The Mystery of the Spiteful Letters: Book 4

The Mystery of the Hidden House: Book 6

The Mystery of the Invisible Thief: Book 8

The Mystery of the Missing Necklace: Book 5

The Mystery of the Disappearing Cat: Book 2

The Mystery of the Secret Room: Book 3

Five On A Secret Trail: Book 15

Five Go To Billycock Hill: Book 16

Five On Finniston Farm: Book 18

Five Get Into A Fix: Book 17

The Castle of Adventure

Five Go To Demon's Rocks: Book 19