Twenty years of Harry Potter – the 20 things we have learned | Books | The Guardian

1 Some first editions can appreciate in value pretty fast. There were only 500 hardback copies of Harry Potter and the Philosopher's Stone printed in the first run in 1997, of which 300 went to libraries. If you find one of these knocking about in your downstairs loo - the print line on the copyright page is 10 9 8 7 6 5 4 3 2 1 - it's worth a small fortune. Expect upwards of £30,000 for it. Fun fact: there was one of these in the Daily Telegraph's books cupboard for many years, but it mysteriously went missing in the early noughties. If you're the bastard who stole it, please have a word with the paper's former literary editor, Kate Summerscale.

The release of Harry Potter and the Philosopher's Stone, on 26 June 1997, passed practically unnoticed