Is there any way of getting it back? I'm sure I didn't read it...

It leaves your inventory when you select one of the three choices.

If you're on PC you can respawn it using the console commands, if not then no. Keep in mind that after using it, it is supposed to vanish.

If you get it and haven't read it yet, then you can put it on a bookshelf and and take it off read it , and put it back, then you read it again and get can choose one of the skill paths again repeat this process till you get all of your skills to hundred.

Afterwards, you can come to the forum and complain about how the game is too easy and there's not enough for a level 81 to do.

Haha, I read up about that exploit and it wasn't in my intentions.

I just don't remember reading the book and gaining any skills from it, but I must of read it because it's not in my inventory and not on my bookshelves :/ oh well.

Cheers anyway guys