I went ahead and bought the stage 1 tome from the cash shop hoping to get stage 2 and sell it plus a bunch of forj ore...and what do I find, but the fact that you actually can't sell any of the other tomes. The only thing I can do with it is unlock Forj Matriarch, Rekindled, and I don't think I'll actually ever get to 70 wins on that with my battle pet... this basically turned out to be a big waste of 750 csc... aagghhh wrings hair
Yes, but once you do manage to train your pet enough (or even manage to split those wins amongst multiple pets), you'll eventually get the original tome back, which you can sell!
Think of it for motivation to keep training your pets! Who knows, maybe some day you will really enjoy battling and would have never kept up training if it wasn't for that damn tome. :P.
.... You never get a copy of the tome back? The tome doubles at a book that can be read, so that'd be kind of counter-productive in the profit department (not to mention then people would whine about ALL books being like that... monthly challengers, hair coupon mags, etc).
That said, once you can start beating the hard Forj it does drop parched or singed baguette crystals, which you could probably sell at least c: They're the best mods in the game to date.
Edit: Ahh, yes you do get a third "tome" from beating the hard forj 70 times as well.. but that one cannot be sold or traded either. It's just for unlocking the impossible forj XD;