Some of the definitions are simply wrong, in fact some are so far off that you will wonder if Andre-Driussi perhaps is referring to a condensed, abridged, and slightly altered version of the series. Some very minor terms and characters mentioned in passing only once in the series are described here in some detail, while some important terms, places, and incidents integral to the storyline (such as the Torturer's Guild/Order of the Seekers for Truth and Penitence, to which Severian belonged) are not listed at all.

Many of the definitions are, well, stretched. This book would be less than half the current size if you threw out all of the example sentences. For instead of just giving the definition, pronunciation and etymology of the listed term, the entry in many cases also gives the full sentence (from the book) in which the word was used. This is not necessary, since the entry also pinpoints the book, chapter, and page in which the term was used in the first place. Takes up a lot of space.

Still, this book will save you from browsing through stacks of dictionaries looking for that obscure term.

The definition will not always identify what language the word is, but the careful reader can soon learn to tell if it's Greek, Latin, French, or Spanish (as most of the "foreign" words here are). Some terms are defined in detail; they contain many examples of the word (and sentences/book excerpts), with real historical anecdotes, mythological references, hypotheses, comments, and squiggly line drawings. Some entries are short and abrupt: "marge: margin. (IV, chapter 13, 86)". Sometimes there is no definition at all; all you get for the entry is the sentence the word is in, and the location of the word. I found that rather odd. In some entries, more emphasis is given to explaining the mythological or historical figure rather than the book character (Wolfe named a lot of his characters after saints and Biblical characters).

Naturally, this book is full of spoilers. If you aren't at least halfway though the New Sun series, be very careful using Lexicon Urthus!

This book has been useful to me, but it's also full of stick-um notes and corrections I had to add myself. It didn't quite do Wolfe's masterpiece justice.

7 of 7 found the following review helpful:

Charming and informative though not entirely dependable  Oct 01, 2005
By Christopher Culver
LEXICON URTHUS is a dictionary prepared by Michael Andre-Driussi of the unusual words and names used by Gene Wolfe in his four-volume masterpiece The Book of the New Sun (and its coda THE URTH OF THE NEW SUN). Those who have read Wolfe's work know that he usually allows many of his archaic terms to be defined for the reader through context, but those wishing to know more about these words weird and wonderful can turn to this resource.

The book doesn't limit itself merely to terminology, however, but also contains the names of characters and places. Many characters in the Book of the New Sun are named after obscure saints of early Christianity or the Middle Ages or mythological figures, and Andre-Driussi shows why they have the names they do. For example, "Nilammon", the man mentioned in passing by the caretaker who shows Severian a picture of the moon ("Now there's trees enough on it to hide Nilammon") is named after a 4th century Egyptian saint who hid in his cell to escape a mob that wanted to proclaim him bishop.

Yet, Andre-Driussi sometimes goes astray. In the entry on Valeria, for example, he mentions several female saints, but doesn't mention who, I would say, is the most likely namesake of the character: Claudius' wife Valeria Messalina. The name of "Kim Lee Soong", the ancestor of the prisoners in the antechamber, is said to be Chinese, but clearly it is Korean. And occasionally Andre-Driussi makes pronouncements that are simply beyond reason, such as that Hethor is the same as Soong. The work is also clearly an amateur production, although Sirius Fiction has typeset and bound it quite nicely.

Educated readers will already recognise many of these etymologies, and LEXICON URTHUS is no substitute for the Oxford English Dictionary and a good saints dictionary. Still, the book is worth reading for any fan of The Book of the New Sun. Pity that it has long been out print, one hopes that rumours that it will become a print-on-demand title will come to be true.

17 of 21 found the following review helpful:

A wonderful guide to a magical series.  Jun 15, 1998
By arist@concentric.net
This book is really only for serious fans of Gene Wolfe. But if you fit that description, you should own this book. Lexicon Urthus is a brilliantly executed dictionary of Wolfe's Urth of the New Sun books. It includes not only definitions of all of the odd and wonderful words that Wolfe uses so well, but also entries for major characters and concepts of the series. Not only is the lexicon a good guide to Wolfe's world, but it is also a great treat to browse through at random. Even though I have read the New Sun books more than once, I still find new insights in Andre-Driussi's work.

1 of 2 found the following review helpful:

A must for lovers of the series  Mar 12, 2010
By C. Singleton
If you have read and re-read Wolfe's masterpiece, The Book of the New Sun, and loved the experience, but felt you were missing out by not knowing many of the words within, then this book, Lexicon Urthus, is a must have for you. Not only has the author painstakingly traced down each obscure word Wolfe used in the books, he gives their history and origins. Every place and character name in the Book is listed here with info for each one. There are several maps, a wonderful synopsis, and an intro by Wolfe himself. I applaud Michael Andre-Driussi for what must have been a very long and challenging book to put together. And, most important of all (to myself, anyway), the book is just a ton of fun to read, skim, or flip through, evoking Wolfe's Urth almost as potently as the series itself. Brilliant. Probably the only reference work I have read for pleasure.