I don't like a lot of photography books, but there are a couple of gems out there.
The Rant
I find the majority of photography books way too simple. I can't think of another subject domain that has as many basic guides written for the adult reader. Even basic cookery books have more advanced content than the basic photography books. Yet photography is an area where there's a plethora of "how to use your new digital camera". The better ones explain more about aperture, shutterspeed, depth of field, etc which generally aren't foremost on the users' minds when they've got their compact camera out. I think it's to do with the fact that it has been a blossoming market for the last couple of years as people rediscover their old talents or discover photography for the first time, especially as small compact cameras have become a consumer standard. Add to that the fact that it's easy to grasp the basics, then you end up with a lot of books designed for the first-time user. Sadly many readers would do better with their camera manual rather than buying yet another basic book which covers much the same information.
The second type of book details photography software and how to use it. They don't always specify that on the front cover, but you quickly realise that case when you delve inside. If you're not used to the software, then you could be thinking that you've picked a book on the wrong subject. In a way, maybe you have in that case, but the gap shouldn't be as far as it seems. A problem with this type of book is that they quickly become out of date as the software is updated.
The third type is the photographer collection and albums. These are great for inspiration, but some fall short and end up being just a bunch of pictures. Fine in their own right, but provide little to learn from.
So where do you go from there?
I'd recommend looking in second-hand bookshops for a used photography book. If you can get the Adams' books mentioned below, then great, but they hardly ever appear second-hand. Even the large photography books from the 70s and 80s are still useful. The photo examples will appear tinted and/or faded compared to today's high-colour glossy images and a lot of the style will also be old compared to today. However a lot of the techniques for composition, use of depth-of-field, soft-focussing, etc, etc will still be valid. What they will miss out on is the advances in the digital era. However a lot that applies to film can be applied to digital, even a basic understanding of film-speed settings is relevant.
My guess is that decent bookshops are weighted towards the lower end of the market with:
The books I like
So far, I've only found a handful of books I like.
I'd bought two of Martin Freeman's books without realising they were both by him. To be honest, I hadn't looked at the author's name, I picked the books based solely on a quick look at content.
The first book is Black and White: The Definitive Guide for Serious Digital Photographers
It's a bit heavy on the software side for my liking, but being pragmatic, I can't see a way that you can discuss this subject area without referring to the post-processing options now offered by software. It does assume a basic familiarity with Photoshop if you're going to follow the examples. I find that Lightroom is sufficient for the majority of my processing, so I had to bear in mind which features were and were not present in that application. Even so, I still found it a useful read. From the non-software point of view, the author provides good examples of what to look for when shooting. From the software perspective, the author discusses several methods for turning a colour photo to black and white, complete with the pros and cons of each. Despite it's size, the book is a very quick read, yet still full of information.
The other book is The Photographer's Eye: Composition and Design for Better Digital Photos and one of its best features for me is that it focusses on the thought that goes into getting the right image. The digital nature of modern photography takes second place. That's a good thing in my opinion. there are enough books about digital photography and how to use the software that what's been missing is one about why we use the cameras in the first place.
The author presents examples and analyses them. It's a great way to expand your knowledge about this critical area. Even taking a chapter at a time will result in plenty of new ideas for you to try.
Ansel Adams
It'd be difficult to talk about photography without mentioning Ansel Adams. Apart from creating classic images and being very influential in the field even after his death, he also wrote a number of books, most accessible of which are:
Your mileage will vary with these books depending on how much you're interested in the mechanics and internals of the camera, the processing routines used on negatives and the zones system. But wherever you come from, they provide a good grounding in photography and many of the features are still translatable into digital photography. I'd suggest you try to have a look at the content of each before buying or at least read some reviews.
Lightroom
I've been using Adobe Photoshop Lightroom for a while now. The printed manual that comes with it is basic and shows the functions, but not why. Most of them are easy to understand if you understand the principles behind them. The electronic guide is more useful but still lacks. I bought The Adobe Photoshop Lightroom Book: The Complete Guide for Photographers to further my understanding of the application rather than photography. It's a well-written book and I do recommend it if you use the software. My main gripe is that the book version I have is for Lightroom 1.0 whereas Lightroom 1.1 added many new features. Don't underestimate the number of features added in 1.1. It was a massive change. And now we're further on than that.
The book includes a code to download a substantial update to the book as a pdf from the publisher's site. It has to be substantial due to the number of changes in the application. It now makes it awkward to use and I'm left with the question, do I use the update or the hardcopy when I want to check something?

"The Photographer's Eye: Composition and Design for Better Digital Photos" (Michael Freeman)

"The Adobe Photoshop Lightroom Book: The Complete Guide for Photographers" (Martin Evening)

"The Negative (New Photo)" (Ansel Adams)

"The Camera (New Photo)" (Ansel Adams)

"The Print (New Photo)" (Ansel Adams)