| 1 person marked this as a favorite. |
It's pretty clear how the tomes work by RAW. Convince your GM make them stack in your home game.
Nothing to see here.
Them not being stackable make all books below +5 a waste not worth keeping ever or even using. Just sell and buy the +5 one or craft your own or cast wish 5 times in a row.
That's pretty silly, you know. If a low level group runs across a Tome of Understanding +2, the party cleric isn't likely to feel that it's worth it to wait the long levels until it's possible to find or otherwise obtain a Tome of Understanding +5, just because a Tome +5 acquired at that point won't stack. That cleric will want the extra bonus to DC and number of spells cast per day now, even if it isn't as big as the bonus they hope to get later.
It is true that this is in some ways a carry over from earlier editions of the game, in which gear could only be found, not upgraded. If you got a +1 sword, you replaced it with a +2 sword, and eventually (with any luck) with a +5 sword. You didn't take your first magic weapon in to a crafter to have it personalized as your wealth increased.
Nowadays, it is very possible that in many games the nicest gear that players have is crafted specifically for them, and is upgraded as needed and possible. Even now, though, that is not true in all campaigns. In some, GMs do not make obtaining enchanted items very easy. Buying permanent magic items is off the table, especially powerful magic such as the various Tomes and Manuals.
Also, it is worth noting that if these bonuses stacked, the same PCs that got them the first time around would always try to get them later. As they don't stack, the other members of the party can possibly get some use out of them and upgrade their PCs without the already boosted PC's player feeling resentful that he or she did not get an item that was best suited to his or her character.
I do the stacking houserule when I GM, but the reason they don't (aside from the language of the spell) is clear. It's much easier to buy something worth 27,500 gp five times than it is to buy one thing worth five times that once. Opportunity is more limited. Resources are more limited. Etc.
It would be reasonable to let the books stack if read consecutively (as with consecutive Wishes).
I much prefer that they don't stack in general. If they did stack, most casters hitting 11th-13th level would be very hard pressed not to just start buying them with every bit of their gold as they can, competing in the spell DC rat-race. Not stacking adds a lot more variation as to when they are purchased, and what other gear is bought in the meantime.
It also adds a party negotiation factor - where a Ranger with a 13 or 15 Wisdom might snag the Tome of Understanding +1, while the Cleric holds off for a bigger bonus later.