Scope of the book

One big learning for me from writing a book on software security is realizing the importance of context to security. There was a constant challenge of discovering the right scope — what needs adding, and what can be cut to keep it concise. Each chapter of the book could well have been an entire book itself, but nobody is going to read what would consume a foot of shelf space. Software security can go wrong in so many ways that there is always more to say, different approaches to take, various pros and cons of different mitigations, further interesting details to consider. And of course new vulnerabilities keep popping up, offering more examples to learn from, and suggesting various new mitigation techniques that might have prevented the problem.

After having chosen the right content, the writer must anticipate what the target readership already knows. When you start writing the question of what the readership already does or doesn’t know, and therefore what you need to explain arises and reveals how imprecise one’s notion of this is. Balancing between losing some readers by providing too little background, against boring the more knowledgeable with too much is one of those judgments with no clear best answer even with perfect future information.

There are other formidable challenges to determining the scope and content of the book as well. When writing about material that one knows best, it’s exceptionally difficult to recall how you learned it, and what the beginner’s mind needs in order to learn.

And then there is the question of what topics to cover, and in how much depth. I decided early on that a complete compendium of every known software vulnerability and mitigation would be so voluminous that, even if I cataloged it, likely nobody would ever read it all anyway.

In the end, I chose to fall back on my personal experience which spans enough years to give a broad perspective. My target reader is an amalgam of people I have interacted with professionally: fellow programmers, but also managers and various specialists who don’t write code but are deeply involved in the software process. It’s admittedly an arbitrary criterion, but to the extent that it works, it solves these problems nicely and provides clear guidance that led me through the writing.