Hi Nicky. That's not as simple a question as it might seem and different publishing houses have different ways of showing what is a first edition. Terry's books have differences in them as well.
As far as the newer books are concerned, you need to go a couple of pages into the book to the page with the details of publisher etc. and look for a row of numbers that look like this: 1 3 5 7 9 10 8 6 4 2
If the first mumber is a '1' then you have a first edition. Hope that helps.
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