This book is a collection of articles from the periodical "Cryptologia" The articles included are mostly recollections of memories from the people that were there, breaking and making codes. A large portion of the book is dedicated to the German Enigma used throughout WW2. This book is unparalleled as a research source and contains the best documentation I've ever seen on cryptanalysis methods employed in the past.

As with a great many books, the title of this book promises more than it delivers. However, it is well worth reading if one is seriously interested in cryptology or the history of cryptology.

Most of the machine ciphers of World War II, and many of the machine ciphers used for a very long time thereafter, derived in one way or another from the ciphers invented by Hebern and Hegelin. For example, the German Enigma was derived from Hebern's approach by Willi Korn, and the American M-209 from Hegelin's approach. The list of machines and designers using one or the other of these two methods would be very long indeed. Alan Konheim's excellent 1981 book "Cryptography: A Primer" deals only very briefly with ciphers of these imortant and widespread types; Deavours and Kruh fill this gap.

"Machine Cryptography and Modern Cryptanalysis" offers a great deal of information on the strengths and weaknesses of these machines, and on the cryptanalytic methods used for attacking such ciphers. It does not discuss a number of other techniques of cryptography, such as NDES and public key ciphers. But what it does discuss is very valuable. Anyone who studies it carefully will wind up equipped to break a wide variety of widely used ciphers.

I would give this book an even more enthusiastic review if it weren't for a problem the authors allude to in the introduction: "The book is incomplete, as it must be. The totality of what happened is buried in a thousand classified documents which will never be made public." Well, that's true, but what's also true is that this book fails to discuss some important stuff on its topic that can be found in unclassified but unpublished documents, at least some of which I feel confident that Deavours was familiar with in 1985, when this book was written. One has to stop somewhere when writing a book; Deavours and Kruh probably made a wise choice about what not to include. But I hope that some day in the near future Deavours (or somebody) will be able to update this book by adding some of what Deavours and Kruh left out.