There is an immediacy and a delicious sense of urgency running through Adam's book that makes the very notion of its foreword almost offensive. "Let's go implement some great ideas", the book seems to rejoice at every page; "I know you don't have the patience but read me first, this may help." I wouldn't want to hold you much with a fluffy, needless opener for a book that in turn frames itself as a prelude to many enjoyable hours of spinning code. I'll try to keep this short and to the point—much in the spirit of the book itself.
D Cookbook aims at enabling you to get work done using D, and it is written from the perspective of one who's clearly walking the walk. I know that Adam has leveraged D for years in his consulting gigs, but even if I didn't, I would have inferred this easily. He writes in the factual, no-nonsense tone of the senior engineer who wants to bring a n00b up to speed so they can get good work done together. Adam's use of "you" and "we" nicely orients himself and the reader toward solving a problem together. He's not coy to just tell the reader what to do to accomplish a task, but never comes across as patronizing. Simple explanations pepper the recipes, and there's always an implied "here's something I tried and works well, you may find that useful" lurking in the subtext.
The book covers a variety of topics that appear to be only loosely connected: what do (to quote a few consecutive chapter titles) "Ranges", "Integration" (with platforms and other languages), "Resource Management", and "Wrapped Types" have in common? Usefulness, that's what. Such topics, and everything else that the book sets out to explain, are likely to be important in real-world D applications. Of these, a few are "canon". At the other extreme there'd be borderline apocryphal stuff such as the Kernel in D chapter. Finally, the bulk of it is annotated folklore (idioms and patterns known by D's early adopters but not yet by the wider community), mixed with the author's own insights for good measure. Such a collection of relevant, high-impact topics is difficult to find collected, let alone in book format. You should read this book if you want to ramp up to using D in industrial-strength applications.
Adam's style is refreshing for someone like me; I've been involved in a mix of language design and language advocacy for years now, both fields of considerable subjectivity and fervor. Adam's dispassionate take on language advocacy is a breath of fresh air. His passion is expended on building great systems, and the language is but a means to that end. If Adam likes a language feature, he does primarily because he can use it to good effect, and proceeds to illustrate that. If, on the contrary, he finds a shortcoming, he simply discusses possible workarounds; that, and the missing lamentations, wonderfully imply that the point of it all is to get work done. "There is one disadvantage", Adam notes in a sidebar, "to operator overloading being implemented with templates, though: the operator overload functions cannot be virtual." Before even finishing that sentence, I've evoked in my mind enough pros and cons for a lively talk show debate. He's unfazed: "To work around this, write the overload implementation as a final method which merely forwards the request to a virtual method."
Last but not least, I took pleasure with the varying "zoom level" of the book. Like a philosopher who also knows his way around a welding machine, Adam can discuss esoteric code generation topics and show code disassembly, sometimes within the same chapter (see for example, "Code Generation") and all in style, while illustrating a good point. Wherever you dwell on the high-level/low-level continuum, it's likely you'll find ways to expand your range by reading D Cookbook.
Many years ago, while in the military, I learned to shoot the famed Kalashnikov AK47. I was bad at shooting from the hip (which is odd because everybody in the movies is great at it) until one day I learned a trick that was doing the rounds—wrap the weapon's strap tightly around the left arm at the elbow. The extra tension increases hand stability. That hack worked great; yet it was not to be found in any doctrine or manual, and in fact I couldn't find much about it today on the Internet. D Cookbook reminds me of that hack—it contains advice that's hard to find in the official documentation, and of immense practical utility. If you want to work in D, you'll find this book a great companion.
Andrei Alexandrescu, PhD
Research Scientist, Facebook
Author of The D Programming Language
San Francisco, CA, 12th May 2014