If you haven’t read any of the series yet, our advice is this: before you start, tell your friends (and even your family!) you’ve gone on holiday for a few weeks, to somewhere you can’t be reached, not even by carrier pigeon. Because you will become hooked on these books. And then the last thing you’ll want is interruptions.
The eISBN (that book’s unique identifier) is 9781905537648. Just search for that if you have any problems.