i always liked the idea of a book box to keep treasures in (or a book clutch, although i can't imagine they'd be big enough to fit all the standard handbag stuff in...), but i never seemed to get around to making one. then my mother asked me for one for her birthday, here's how that went:
they're not difficult to make so much as time consuming - you want a fairly thick book so that you can actually put stuff in the box, but that means that you have more paper to cut through. and no matter how sharp your craft knife is, you will most likely get half way through and get annoyed and start just hacking at the pages you have left to cut through. DO TRY AND AVOID DOING THIS as you really want the inside walls of your box to be neat. i cheated, i mean, i hacked away at it and then concealed the mess by lining it with card covered with an old map. you can do this too as it totally worked out fine.
this is one of my 'here's one i made earlier' things so there's no step-by-step photos i'm afraid. it's pretty much how you might picture it though - be smiley and polite to the ladies in the secondhand bookshop as they scowl at you and tell you cutting up books is sacrilegious, get book, cut a hole in the pages of said book, hold book shut while applying glue to the edges of the pages, panic when you realise that you didn't put a sheet of greaseproof paper between the top cover and the pages so that it wouldn't all stick together, carefully pry the top cover away from the rest of it - damaging it in such a way that you now have to paint everything to conceal the gluey mess, line book box with a snug, much thinner and prettier card box, glue that in place, then pretend it was all intentional as it turned out rather well in the end.