For anyone studying security and looking for an accompanying textbook I would expect this title to be extremely useful. It provides a good introduction to cryptography without assuming prior knowledge, however if you have limited experience of mathematics and formal specification you may have difficulty with this book. All the relevant number theory is presented just before it is needed, which is excellent when reading it for the first time, but means that the information is hard to find when attempting to refer back to it at a later date.
The largest problem from a casual reader's perspective is that this title appears to be written as a textbook - every chapter is broken down into explanations followed by examples and exercises, whilst this may be useful for a beginner it detracts from its usefulness as a reference book and makes it difficult to read. As you would expect the material covered is recent and all the common secret-key and public-key encryption algorithms are explained; a nice feature is the pseudo code implementation examples that support the descriptions of the algorithms.
In conclusion I would say that for anyone not mathematically minded there are far better titles available, however this book would find its place in the collection of anyone wishing to understand the detailed theory behind cryptography.