I initially sampled eBook to make sure there was no glaring issues in the text as what tends to happen in lazy text to digital translation. I noticed the access left understandably blank. Purchased at the lower digital price assuming that would display once fully downloaded. Looked on the page after and still blank. No indication anywhere to an added page containing the code to additional sources. Cost of access code through Pearson's brings total cost up to be comparable to physical version in my college bookstore, which I know has the code. Immediately returned so I can purchase a COMPLETE book.

This book is intended to serve both as a textbook for an academic course of study, and as a self-study and reference guide for practicing professionals. The material has been extended to emphasize encryption and its central position in network protection. The structure and flow have been reorganized with both classroom use and solo instruction in mind, and additional teaching material, such as additional problems, have been added.
Chapter one is an introduction to the topics to be covered. In a practical way it outlines the concerns involved in the phrase computer security, and the priorities occasioned by the networked nature of modern computing. There is also an outline of the chapters and sequence in the rest of the book. While the text does note that cryptographic techniques underlie most of current security technologies this is only done briefly. Examples in the major categories listed would help explain this primary position.
Part one deals with conventional, symmetric, encryption and the various methods of attacking it. Chapter two covers the historical substitution and transposition ciphers. Symmetric block ciphers are discussed in chapter three, illustrated by an explanation of DES (Data Encryption Standard). The additional conventional algorithms of triple DES, IDEA (International Data Encryption Algorithm), and RC5 are reviewed in chapter four. The use of conventional encryption for confidentiality is outlined in chapter five.
Part three looks at public-key encryption and hash functions. Chapter six introduces public-key encryption and its uses in confidentiality, authentication, and key management and exchange. Number theory is the basis of these modern algorithms, so some basic mathematical concepts are outlined in chapter seven. Digital signatures and message authentication is introduced in some detail in chapter eight. The algorithms themselves are explained in chapter nine, including MD5 (Message Digest algorithm), SHA (Secure Hash Algorithm), and others. Protocols using digital signatures are described in chapter ten.
Part three takes this background material and relates its use in security practice. Chapter eleven looks at authentication, concentrating on Kerberos and X.509. The examples of e-mail security systems given in chapter twelve are PGP (Pretty Good Privacy) and S/MIME (Secure/Multipurpose Internet Mail Extension). Security provisions for the Internet Protocol (IP) itself are reviewed in chapter thirteen. Web security, in chapter fourteen, again concentrates on protocol level matters, but also discusses the SET (Secure Electronic Transaction) standard at the application level.
Part four outlines general system security. To the general public the primary concern of security is to deal with intruders and malicious software, so it may seem odd to the uninitiated to find that both of these subjects are lumped together in chapter fifteen. Chapter sixteen finishes off the book with a description of firewalls and the concept of trusted systems that they rely on.
Each chapter ends with a set of recommended readings and problems. Many chapters also have appendices giving additional details of specific topics related to the subject just discussed.

Really bad writing style, very confusing, lots of grammar mistakes. This guy needs an editor really badly. He uses examples to explain examples to explain examples. Nesting "for examples" makes things really confusing. Also, using a term like "process" 4 times in one sentence, where each time its used means something different, means that maybe you should define your terms better and/or find better/other terms to describe what you mean. Also has several cases of circular definitions, like: says that a process is part of/must include one or more programs, but in another section in the same chapter, he says that a program is part of/must contain one or more processes. Now, while this may or may not be accurate, it is also very confusing and needs to be re-written to make it make more sense to layman/students.

I disliked this book immensely (By the way, I noticed some reviews seem to be for different textbooks. My review is for the Operating Systems book). I found several instances of plagiarism (no citations or credit given to original source) including these two examples:

Textbook:
A resource that a subsystem needs exclusive access to at all times. In this class of resources, no sharing policy is needed since only a single component ever requires use of the resource. Examples of dedicated abstractions include interrupts and counters (Stallings 585).

Plagiarized from:
An abstraction is dedicated if it is a resource which a subsystem needs exclusive access to at all times. In this class of resources, no sharing policy is needed since only a single component ever requires use of the resource. Examples of dedicated abstractions include interrupts and counters (Klues, Levis and Gay).

Textbook:
Every client of a virtualized resource interacts with it as if it were a dedicated resource, with all virtualized instances being multiplexed on top of a single underlying resource (Stallings 585).

Plagiarized from:
Every client of a virtualized resource interacts with it as if it were a dedicated resource, with all virtualized instances being multiplexed on top of a single underlying resource (Klues, Levis and Gay).

Not only did the author plagiarize, he seemed to relish writing in a verbose manner. For example, this is his explanation of deadline criteria: "When process completion deadlines can be specified, the scheduling discipline should subordinate other goals to that of maximizing the percentage of deadlines met.” He couldn't just write that the maximum number of deadline should be met? This is typical, and it makes reading this textbook a chore.

Works Cited
Klues, Kevin, et al. "Resource Arbitration." Documentary. n.d. Web.
Stallings, William. Operating Systems: Internals and Design Principles. Upper Saddle River: Pearson, 2015.