Hi,
I'm 15 Years Old - and the closest thing you will ever find to an expert on all major fictional spy series ever published in English, From James Bond - to Cherub and Alex Rider - without talking to the authors themselves.
I bought the entire series at once, after emphatic reviews of "Lionboy" claimed it to be a brilliant read. I have to completely agree. The concept of a boy speaking "cat" is fascinating, and one that I have never remotely come across in the hundreds of children's and teenage fiction books I have read. Corder (the name adopted by the two authors) has a fantastic writing style, that is both intelligent and inthralling, allowing you to appreciate the book as both a brilliant read and a genuinely well written piece of literature. The language is not too demanding for a well read 11 or 12 year old, though I would advise 13 and upwards as a benchmark, as the language does get more difficult at times. That would be the only thing I could see putting some children off. Please do not think I am specifying children to read this though. I would encourage everyone, young and old alike, to try this book, and the entire series with it. It is completely original, and completely brilliant.