First of all, this book is written for fans of Roger Zelazny and his "Amber" Universe. It is a guide to the Castle (one of the recurring settings within the tales) and some of the castle's surroundings, inhabitants, etc. If you are NOT familiar with Zelazny's Amber stories, you should avoid this volume, as it would fill you with misunderstandings and the occasional "spoiler" that happens to be accurate. If you ARE a fan of Zelazny's Amber books, you want to avoid this book at ALL COSTS, because it is so full of errors that you'll cringe.
This book is of a genre once known as a gazetteer: a guide to a given locale's places of interest. As such, the primary concern of any modern-day author of such work is accuracy. If one bought a guide to, say, London, the reader would be justifiably upset to find the book full of misinformation, mistakes, and wild fantasies.
Yet such is exactly what a reader finds in this book. It is not understandable: not only did the author have the chance to interview Zelazny, but at the time of this book's writing, there were only a handful of Amber books in print. Surely, the research involved could not have been too taxing? Yet, it obviously was.
Just because the book lists Roger Zelazny as first author, don't be fooled. The text is bland and banal, in addition to the errors. It is obvious Zelazny had little-to-nothing to do with the writing of the book.
The book walks you through the castle, led by one of Roger Zelazny's secondary characters, Flora. The author(s) of this particular book crudely mishandled her persona. The book then provides a discussion of the castle and associated "facts." Some of the facts are grossly misrepresented, such as non-royals going mad if the view the Pattern (an artifact crucial to the tales, and hidden in the bowels of the Castle) Some mistakes are so ludicrous that one is left either a) rolling one's eyes or b) laughing out loud. The degree of care that went into the writing of this book is told by none other than the presumed main author, Neil Randell, himself. According to the book's Introduction, while colleagues were interviewing Zelazny, he was off reading the draft of Roger's next book! Talk about missed opportunities and misplaced priorities!
Another side effect of the book also made it obsolete: Zelazny so disliked being bound by the descriptions in this book that in his next novel, he had a large-but-unspecified section of it destroyed so that it could remodeled any way he wished. So, in the end, the book is doubly useless: not only it is full of misinformation, but it was obsolete as soon as Zelazny could make it so! Don't waste your money!