The note to you is an item found during the Ritual of the Mahjarrat quest. In the note, Robert the Strong explains that the enclosed Robert's necklace and Note to robert are to be given to him once the player meets him in his human form.
The note to you also says that Robert has hidden several items around the island of Kethsi to aid the player in completing the puzzle to gain access to Dathana's message. He also reveals the fairy ring code DKQ, which leads to the Ritual plateau.
After Ritual of the Mahjarrat, the note can be used on Bob the cat which he will find shockingly interesting.
It is unknown if this note will have another use at some future time, such as when the player meets Robert the Strong again. Even if so, for players wishing to save bank space, the note can be destroyed, as it can be reobtained in Kethsi.
Welcome to Kethsi. I'm sorry that I have no means of knowing your name. I don't have much time before the magic takes hold and my reincarnation takes place.
I also enclose a note to myself, which you must give me when you see me, but NOT as a cat.
I enclose a necklace crafted by my sweetheart, Ilsinor. there is no other like it. You will need it to convince me that the note I sent myself is worth remembering.
There is information on this island that will be needed if the enemy is not to overtake us all. It's protected by an ancient Kethsian puzzle. I enclose vital items to help you complete that puzzle. I hid them here many years ago to keep them from getting into the wrong hands.
-Robert the Strong