There's something of an unseemly struggle going on in children's publishing in the UK, usually a very civilized place. Most of the children's publishers feel it would be a good thing to put an age label on the back of the book, along the lines of 9+, 11+ or whatever to indicate the target age range. A large group of authors, including big names like Philip Pullman, plus many librarians, are dead set against it.
You can see the anti-banding concerns at their website. In essence the argument is that many people either to match their ability or for fun like to read books that technically aren't aimed at their age group. Putting suggested limits on a book would stigmatize those who like to read a 'younger' age book, and put young people off stretching their reading beyond their age band.
The publishers, genuinely bewildered by the reaction, I think, don't see the problem. It will just be a little label on the back. Many books are bought by an adult for a young reader, and this will help them choose something appropriate.
I have to admit I can see both sides of the argument. I know just how sensitive children are - anything that suggests they are reading something for a younger child will put them off, and the last thing you want to do is put children off books. On the other hand, it can be difficult to know what will work for your friend's eight-year-old when buying a present. Some kind of guidance in the shop is handy.
In the end, I signed up with the No to Age Banding site because I think the labelling misses the point. Labelling on shelves already directs people in bookshops and libraries to the right kind of books. But by not putting the label on the book itself, there's no stigma to being seen with a book that's 'too young for you'. There is simply no need for age banding, it could put some youngsters off, so let's do away with the idea and move on.