The Chronicles of Amber (R. Zelazny, 1970-91)

Amber and the Courts of Chaos are the only two true worlds; all others, including our Earth, are but "shadows" of the tension between them. Royals of Amber who have negotiated the Pattern, and the equivalent Chaos nobility who have navigated the Logrus, can freely travel through the shadows and alter them, but they cannot alter Amber itself.

Corwin wakes up in a hospital in New York from a coma with amnesia. He escapes, tracks down his sister Florimel, and discovers that he is a scion of the ruling family of Amber. He is taken by Random to walk the Pattern, a labyrinth inscribed in the dungeons of Castle Amber which gives the multiverse its order. Walking the Pattern restores Corwin's memory and his powers to travel through shadow. He attempts to conquer Amber, which is currently ruled by his elder brother Eric, but fails and is blinded and imprisoned. Blindness removes his two possible means of escape; walking through shadow, or using the Trumps (i.e. the "major arcana") of a tarot deck which allows communication between members of his family. He regrows his eyes, and thanks to a chance encounter with Dworkin Barimen, the mad sorcerer who created the Pattern, he escapes. He discovers a threat to Amber, a black road which runs across universes from the Courts of Chaos to Amber, created by damage done to the Pattern by his brother, Brand.

Rating: 9/10

The first five books describe the adventures of Prince Corwin of Amber:

Nine Princes in Amber
The Guns of Avalon
Sign of the Unicorn
The Hand of Oberon
The Courts of Chaos

The second series tells the story of Corwin's son Merlin (Merle), a wizard and computer expert. These volumes are:

Trumps of Doom
Blood of Amber
Sign of Chaos
Knight of Shadows
Prince of Chaos