Lumeinshin
I've never had hands straight enough to modify anything physically, except for soldering several blue LEDs into my old mouse once and swapping wheels on several 1:64 car models. I wish I will repaint the case of my PC one day, but this remains a very distant dream, pretty much like repainting 1:64 models. Modifying books sounds just as neat, and I wish I could just add some kind of a lock and chain on my Book Of The Dead, simply to care it around in kind of a goth style.
As I've said, I suck at it. At best I can repair some things, like re-soldering couple thingamabobs in a gamepad or whatever, but all my attempts at modding anything so far were very, very mediocre. In fact, the original was right away ruined, and I do not have money to buy any more proxies for practise... practice... practise... whatever.
My modding strength lies in the coding and other digital mediums. At least there you can have backups and have infinite tries to polish your skills. Frankly, I wonder why so few people are doing that and some of the people I know call me the "tech wizard" - I'm not even doing anything special. Guys who run debuggers and manage to de-cipher encoding of the file formats - now they are wizards, and they are way above my level.
TL;DR: sounds neat; I can't do it.
Edit: actually, I have two more examples of me physically modifying things. Nothing related to books though, but still, I think I should mention them to be completely fair.
First, I've painted my table. Decent job, but I've forgot to cover it with a layer of lacquer, so nowadays the paint is all chipped and dirty. I really should disassemble the table and re-do the job not forgetting the lacquer this time, but since it is my working table which I am writing this message at right now... yea, you guessed it. Well, at least it looked somewhat cool when it was fresh.
And the last is the fact that I've disassembled my external CD drive and repainted it's upper part into light blue. It was white, and I've just covered it with a layer of blue from a can of Montana Black. Now that turned out to be surprisingly solid job - aside from small imperfection where I was holding it with my fingers, the paint somehow turned out to be pretty much perfect. And it still is, to this day. I guess, that's the best I've ever made, even though it is just a solid blue color without anything fancy.