Monster book is bland. You kill monsters, get more drops, a slight exp bonus, and you move on. How about an extra reward for your efforts?
Introducing the revolutionary Monster book rewards! Completing a whole page will give you an amazing item/weapon! Ex. completing page 1 will give you a lesser reward, because its easier, maybe a great ATK scroll, or a small amount of money (like 20 silver.)
The higher the number it is, the more rewards you get! (Complete the red tier, you can get a cursed scroll, or a god tier weapon for your faction, or a high amount of money, 60 silver.
Complete more pages, get more rewards, that’s about it.