Having examined this fascinating book on codes and ciphers, it took a great effort to resist the temptation to produce an encrypted review, so atmospherically is the material presented. The introduction traces briefly the history of the subject, and gives some pointers on terminology. The main part of the book comprises an alphabetical sequence of entries on cryptological topics, ranging from the classic, such as the German Enigma machine, to the very arcane, such as the Diffle‐Hellman Key Exchange. This is followed by an appendix on the Data Encryption Standard, a bibliography of books, articles and Internet sites, and an alphabetical index.
In the main section there are many entries, quite naturally, for codes developed in the context of wartime or espionage, but the author has also drawn examples from literature and from the history of language. As well as treating concepts, the book covers people, and there are some entries for printed and electronic resources. Entries range from the short to the very substantial, and most end with a mention of other relevant entries and an indication of suggested further reading. The descriptions of different systems of encoding are generally clear, with good use of diagrams and examples. Some entries in the main sequence are simply references to other entries, a practice repeated in the index at the end. This index, in fact, is a little disappointing, in that it largely reproduces the order of the main section, including the cross‐references, and although some other index entries have been added, no attempt seems to have been made systematically to index the content of the main entries. A more analytical index would be more helpful. The passage on smoke signals, for example, in the entry for signal communications, cannot be traced through the index, but can only be found by scanning the entry itself and happening upon it.
I have a number of slight concerns about the book’s content and treatment in some places. There is an entry for Personal Identification Number in both main sequence and index, but no cross‐reference for PIN in either. The description of the use of bar codes is couched very much in terms of the Universal Product Code, with no obvious mention of other applications, such as their use on personal or identity cards, as means of registering memberships or using services. I expected to find a specific mention of the ISBN, but did not. My other concerns arise from the inescapable fact that this is an American publication. There is an entry for zip code but not for post code, and there are entries for hobo code, argot and jargon code, but not for Cockney rhyming slang, which would be entirely appropriate in the context of these other entries. However, these are relatively small points, which do not substantially alter the fact that this is a good reference book, which has been well‐researched, and which presents sometimes difficult but compelling material in a clear and careful way, without losing the interest. It is very good value for money, and would be a good addition to the reference stock of all but the smallest collections.
