Zelazny is writing a novel about Prince Corwin of Amber. But he's releasing each division as he finishes it, [The Hand of Oberon] being fourth in the series. It begins with the next paragraph after the end of Sign of the Unicorn, its predecessor, and concludes with a cliff-hanger that will be resolved in the next.
This creates some problems for the reader. Much dialog is background-as-conversation, never an easy trick, though Zelazny usually keeps one's interest. Even with a chapter-long flashback written to summarize past events, there is sometimes the feeling of having missed something important. Names are thrown at the reader, who may only learn some pages after the fact why the characters reacted as they did, the full explanation being in an earlier book.
Zelazny is inventive and knows how to use language. His description of Corwin's hellride from Amber to Earth is practically a cinematic montage….
Corwin is a prince of Amber, the only true reality. All other worlds, including our own, are Shadows of Amber. Shadows that can be shifted or traveled between by Corwin and his family. Caught in the middle of a fratricidal struggle for Amber's throne and facing an invasion of demonic forces from without, Corwin struggles for answers in Amber, in Shadow, and in such realms between as a floating city visible only when the moon is seen in full.
Keep in mind my warning, but try this book. Better yet, read the series. It may be years before the work appears as a single volume, and it is too good to wait that long.
Lew Wolkoff, "Fiction: 'The Hand of Oberon'," in Best Sellers (copyright © 1976 Helen Dwight Reid Educational Foundation), Vol. 36, No. 6, September, 1976, p. 188.