The tome of Darkness do when read to a pet?

Raises: 1-3 Points of Level, 1-3 Points of Strength, 1-3 Points of Defense, 1-3 Points of Health.

(Most info about what certain items do can be found on SubetaHQ.com ^^)

...I haven't used one yet, but isn't there a difference between 'read to' and 'use on'?

There is no "read to" option on tomes, only "use on."

Ahhh. I didn't know that, I'm cheap and usually sell my amulets. Thanks :D