My first point is in response to other review writers: to call this book "out of date" is disingenious. Whilst it does make references to some specific, no longer produced, emulsions (i.e. makes of film), the impact of what is being said is not lost because of this. In fact, even if he had written this today, he could have picked emulsions that you as a specific photographer didn't like or have access to; the fact that some of the products he talks about are no longer produced, is quite frankly irrelevant.
Whilst, of course, the book is centred on producing a negative, the principles outlined in the text, especially those concerning exposure, not only can, but SHOULD be applied to digital photography as well.
The text is clearly written, does not waste words and is not (in my opinion) particularly difficult to read; I read this book in the same way that I would read a novel, sitting on the sofa with a mug of tea or a glass of wine- NOT studying it like an academic text at a desk!
Adams' discussion of the Zone System is complete, clear and accurate. It is illustrated with beautifully printed examples of the author's own work and includes chapters on how to use filters within the ZS as well as more "advanced" techniques, such as painting with light. (I use speech marks, since the concept is not difficult to understand, but is awkward to put into practise).
Adams' explanation of density-exposure graphs and spectral responsivity graphs is clear and useful, not only to film photographers, but also to those who manipulate their images digitally; the same graphs are used in photo-editing software, as they show the same thing!
Anywho, this is a great book, and don't be put off reading it. If you're interested in photography, just buy it or ask for it for Christmas when you don't know what else to ask for! I really think you won't regret it, and that it will contribute greatly to your ability and desire to make beautiful pictures.