The Tablet is a general term used to describe the original pages of the Book of Prophecy. These pages come in blue, gold, and green. In most cases, blue are recipes for various item codes, gold are instant level ups to your health and mana, and green are puzzle item codes. To open a puzzle item code from a green tablet, you must click the picture on the other page from the book and complete the puzzle. The first I achieved was the Ice Wings.
The tablets are actually pages from the first Book of Prophecy when the hero's world was first created. They are only visible to the book holder and appear in fields, houses, dungeons, and usually after boss battles.
Many of the houses you visit have tablets in them. When you completely explore a house to 100%, usually 1000/1000 on all floors, a tablet spawns.
The Tablet is only visible to you, yet no one will ever stand on them or will cross their paths.
There are different kinds of Tablets. They are easily recognized by their colors.
Blue Tablets - Metalize Tablets. Used for creating and forging more powerful weapons and accessories. For more on these, see Metalize Tablets
Yellow Tablets - Strengthens the Book of Prophecy and its owner, restoring the owner's life and mana, and giving him / her extra points in HP and MP. Usually given after Boss fights.
Red Tablets - The Tall ones increase your HP, while the short ones yield the most powerful weapons in the game. Hidden on some maps until you fully explore that area.
Green Tablets - Like red tablets but the tall ones increase your MP, and the short ones, while still yielding veery good weapons, don't give as good ones as the red tablets