hello ade, thanks so much for this book, it looks fascinating. i've downloaded it and can't wait to read it.
as for copying my code... i'm honoured you felt it was worth copying, but i am not sure it can be considered "mine" ; i've learned most of what i know by studying other people's code and i still like to take a look just to see how other people do things.
it's an excellent way to improve your own coding skills.
three men in particular owes a lot to many other people who helped me hammer out particularly tricky bits, most notably jellby, whose code i highly recommend you take a closer look at (he's uploaded quite a lot of amazing epub books here) ; jellby is the epub king.
now that you've discovered the joys of epub and code and sigil (brilliant editor, isn't it ?), i hope you'll continue to share your epub creations with us. don't hesitate to ask if you've got any questions ; we've got quite a lot of epub experts around here and they are all really friendly and helpful.