Book 1

Book of Names

by John Peel

Published 1 August 1997
The first book of the "Diadem: Worlds of Magic" series focuses on Score, Helaine, and Pixel's thrilling search for who or what has brought them to Treen, a planet on the outer ring of the Diadem. Clues lie inside the tower of a cunning wizard and within a stranger's rhyming riddles. But the quarrelsome trio is ever doubtful of whom to trust-even among themselves. Danger awaits them at every turn as they battle angry mobs, bloodthirsty wolves, and a conniving wizard. Yet their toughest challenge is learning to band together as a team, their only hope against the perilous spells of their one true enemy.

Book 2

Book of Signs

by John Peel

Published 1 August 1997
Diadem chronicles the adventures of three teenagers from very different worlds. Score is a streetwise New Yorker, Renald lives in a Medieval world where she readies herself for battle, and Pixel is confined to a one-room world of Virtual Reality. But now they all exist in the Diadem, the circuit of all worlds where their awesome purpose unfolds.

Book 3

Book of Magic

by John Peel

Published 1 August 1997
In the third book, the young magic-users travel to Dondar, a beautiful land of purple skies and blue grass. It is also home to Garonath, the unfriendly wizard of forms. With help from their unicorn friends, they fight his magical monsters, but they soon fall into the hands of Sarman, the evil magician who wants to rule the Diadem . . . and needs their souls to accomplish his despicable mission! But the ultimate battle lies ahead when they must face the Triad and discover what the mysterious Diadem rulers have been planning all along.

Book 4

Book of Thunder

by John Peel

Published 1 October 1997
Score, Helaine, and Pixel rush to the planet Dondar to rescue their unicorn friends. Thunder, the noble leader of a herd has lost his title-and almost his life-to Tychus, a rogue unicorn who has a "wrongness" about him that everyone senses. And Helaine notices that the herd is behaving oddly, as if under a spell, with Tychus in charge.
With help from their magical guide Oracle, the wizard Shanara and her sleepy red panda named Blink, and a unicorn named Darkstar, the trio learn more about the new leader of the unicorn herd and his devious scheme that will endanger the entire Diadem.

Book 5

Book of Earth

by John Peel

Published 1 February 1998
Score falls victim to a deadly illness with only one cure: stopping the mysterious person behind this magical attack. Determined to save their friend, Helaine and Pixel go to Score's hometown, the Earth city of New York, to seek out his attacker, who is using Score's most precious item to hurt him: his mother's amulet.
Finding the amulet proves to be difficult on Earth-an unfamiliar world of cars, skyscrapers, and guns for Helaine and Pixel-where their magical powers are severely weakened. Luckily, the trio stumbles upon a wealthy businessman who promises to help them in return for curing his disabled daughter-but is he really on their side? And then there's Bad Tony, Score's abusive father, fresh from jail, who shows up with gun-toting thugs to kidnap his critically-ill son. Will Helaine and Pixel find the amulet in time to save their dying friend?

Book 6

Book of Nightmares

by John Peel

Published 1 April 1998
Score is a young street kid from New York City. Helaine is a fierce girl-warrior from the medieval planet of Ordin. Pixel is a virtual reality junkie from the planet Calomir. All from different worlds, these seemingly ordinary kids are brought by some unknown force to the Diadem, a multi-layered universe, where they must rely on their unique magic skills and each other as they battle the evil that lurks within these mysterious and magical worlds.

Book 7

Book of War

by John Peel

Published 1 May 2005
Score, Pixel, and two unicorn friends accompany Helaine to Ordin - a medieval planet of high-brow nobles, oppressed peasants, and endless battles over land. Upon finding her home, Castle Votrin, under siege by the Border Lords, Helaine vows to make it up to her father. With help from Jenna - a pretty, spell-working healer with a crush on Pixel - they struggle against angry villagers, giant insects, and pillaging soldiers to find a way to save Helaine's home and her family honour

Book 9

Book of Reality

by John Peel

Published 1 February 2006
"Book of Reality "finds Score, Helaine, Pixel, and Jenna journeying back to Calomir, Pixel's home planet of virtual reality. Pixel hasn't been back to Calomir since being snatched from the futuristic planet when he was first pulled into the magic and danger of the Diadem. Pixel wants to see his parents again-and bring Jenna home to meet them.
But instead of a happy homecoming, the four young magic-users find treachery, slavery, and deceit on Calomir, including a dark secret from Pixel's past. Can they find Pixel's parents, liberate the enslaved Drones, and win the battle against the evil force that not only controls Calomir, but also intends to conquer the entire Diadem?

Book 11

Diadem - Book of Time

by John Peel

Published 22 November 2012