Writing Prompt: The Diary

Imagine your character just found a diary hidden away somewhere. What do you think the diary would look like? Where might they have found it? What sort of condition is it in?

Perhaps the more important question: Whose diary was it? Did it belong to someone they knew? To someone that witnessed something important happen? Did it belong to their grandmother or another relative of theirs?

Could the diary have belonged to their own future self? What would they have wrote about that they would have felt a need to send the diary back in time? Did they intend for it to end up in their own hands, or someone else's'? Was it someone else that sent it back? Why the whole diary and not just a letter?