I am well aware that i am treading a dangerous line here. Many people fanatically swear by the "Bible" as it is so often called.
I'm sure that at some point, this really was the best book in the business. It has lots of detailed discussion, about almost every area of electronics, often including "real-life" components - very useful when designing circuits. Most of the content is still relevant and there is a great discussion about micro-power and some other subtopics.
The Art excels in its title. There is plenty of discussion about how to go about designing a circuit. Rather than simply give the reader a list of standard circuits (say the myriad opamp circuits, rectifying and regulating circuits, etc) and leaving out the application, the book deals strongly with how to actually put the designs into use. There are (usually in each chapter) often "real world" examples where a believable problem is laid out and a potential solution is carefully examined. Not many books do this and there are some real insightful passages.
Where it falls down, however, is age. Bear in mind that the most recent edition is now over 20 years old (as of last July). 20 years is a long time by most people's standards, but in a field like electronics, that is an age. For instance, this was published before the WWW took off, before OLEDs, etc. Nowadays people are interested in cheap radio frequency/wifi/bluetooth commmunication, components are replaced with more efficient or reliable models and the section on batteries is more or less totally obsolete (for instance Lithium based batteries are now practically standard in most portable electronics).
Sure, the basics of electronics stay the same. Fundamentally opamps are the same as they were 20 years ago, transistors follow the same rules and good old V=IR hasn't failed us yet. However, if you want a beginners introduction on electronics you could look elsewhere. I found that elementary electronics is pretty well explained, but there are better textbooks on the market (see Neil Storey, Electronics: A Systems Approach) for that.
In summary, it's a great book if you're interested in how to apply the principles of electronics - and indeed that is pretty much what it claims to do. However, i would not really recommend using this as more than an occasional reference (particularly with regard to named brand components - many of which have been succeeded). As it stands, perhaps 10 years ago this was the holy grail, but it's slowly becoming a doorstop in my opinion. If they do eventually release a new edition with updated and modern technology then i would certainly give a recommendation to buy.