Even if you have other editions, you may want this one for the wonderful Jeff Jones cover.

Nine Princes in Amber: one of Zelazny's most famous novels - (the original hardcover came out in 1970.) Corwin, Prince of Amber, wakes up on the "shadow" Earth without his memories. Breaking out of the mental institution where he is being kept, he ends up with his sister Flora - but will she help him or is she his keeper? He is contacted by a brother - Random - who is pursued by near-human creatures from another Earth. Corwin realizes he can't trust all of his relatives, and does his best to conceal his ignorance, even as superhuman abilities are revealed and his world-view is continually expanded or exploded. Random tells Corwin they are both princes of Amber - the "true" world, from which all other worldlines are distorted reflections or shadows - and offers to help them travel to Amber, in a hair-raising journey through several strange or nightmarish worlds ("shadows.") During this journey, Corwin keeps recovering little bits of his lost memories - including the fact that he may be a major contender for the rulership of Amber, and that the rivalries involved may have led to his exile on the shadow Earth. More of the brother Princes are encountered, and every one has an agenda... This makes my personal "top 100" list, and I re-read my copy often.