Tomes of damage are stat boosting items in Blizzard All-Stars. Three 'ranks' of them exist.
Cost 350 gold.
Cost 400 gold.
Cost 500 gold. Grants a 10% damage increase. Ability damage, ability healing and shields are increased by 5%.
Blizzard Entertainment. 2011 Blizzard DotA Press Kit. Blizzard Entertainment. Accessed on 2012-05-03