I've stumbled across cryptography for about the past year, so recently I decided to go ahead and learn some basics (as I think the subject and InfoSec is really interesting). Most cryptography books out there are for the advanced and are mathematically rigorous. While I gladly welcome math, I needed an overview to bring me up to speed, prepping me for more intermediate (and eventually advanced) texts later.
I've never read a Dummies book dealing with computer technology before, because although they're written for absolute novices, the low-level writing style irritates me, usually takes too long to get to the "interesting stuff", and the "yippity-skippity!" attitude will eventually make me go seek a more advanced text. Basically, Dummies books "hold your hand", and if this is what you need, they're great! But if not, they can be rather slow for you (as for me).
However, Cryptography for Dummies is pretty good, aside from a few misses. By this being a Dummies book, the impression of this text being for complete neophytes is false - if you don't have any experience with basic computer science topics (e.g. binary, binary-to-decimal conversions, bits/bytes/words, etc.), the first couple chapters may be a little hard to understand, as the author assumes you at least know that stuff.
Aside from that, the author does a good job explaining the basic topics one needs to understand cryptography and its inner-workings. However, the author's writing style leaves much to be desired at times. At points, I found myself scratching my head, re-reading passages several times, trying to figure out what the author meant. At times when he should explain the nuances of something, he doesn't, leaving you to go, "HUH?" (A good example of this are the early parts where he talks about keys but doesn't explain what a key is or how they interact with other parts of a cryptographic system.)
There are other sections where the author leaves entire descriptions of things out, where you'll have to figure it out for yourself. Perhaps this is purposeful, so he won't get too far into the topic, as this book is basically an overview. Something else I noticed too is the vast amount of errors the book has! I'm not sure if Dummies has an 'Errata' section on its site.
While this book is by no means a complete text (probably not even a 1/3-complete text), overall, it's good for those who want an overview of the subject, and plan on venturing further, as I do.
