Looking at the spoilt preview cards for Blood of Gondor and the Morgul Vale it looks like we are getting two cards with the ability to play an event from your discard for leadership and lore.
Text on the Tome seems to read :
"Attach to a leadership hero. Reduce the cost of playing Tome of Atanator by 1 for each hero you control with the leadership icon.
Exhaust Tome of Atatnator to play any leadership event in your discard pile as if it were in your hand. Then place that event on the bottom of your deck".
Looks like the lore version does exactly the same thing for lore.
These look like pretty powerful cards right ? Can already see some combos with lore's card draw events.