Whispering Tome of Wisdom

Some wisdom is not meant for mortal men. It will make you see the world as it truly is - maybe you won't like what you see.

The Whispering Tome of Wisdom is an artifact from an unknown creator. There are multiple stories of powerful wizards using and then apparently destroying it. However, it seems to always turn up a few years later, ready for the next brave fool to exploit.
From the outside, the book seems fairly remarkable. It is bound in green tinted leather with a golden cord wrapped around it. The cover spells out the name "Whispering Tome of Wisdom" to the reader.
When opened up and read, the tome seems to describe very basic concepts of magic or items or other concepts. Upon reading it, however, the reader immediately begins to understand a wide range of topics in an increased rate, even without reading about it.

Please. The whispers. Make them stop. Someone. Make them stop!

However, every owner of the tome has gone mad so far and most casual readers also complain about halucinations and experience some form of paranoia. They all describe constant whisper from the tome, begging the reader to contrinue reading it.
Over time, the tome apparently has shifted its appearance, to adapt to the current times. Who knows how it will look like now?

Show spoiler

Do you hear the whispers?

Ingame Mechanic

Effects

Raising Wisdom only requires a quarter of cost

Drawback

Randomly gain levels of insanity with every level up