Next: A book entitled "Things I Wish I Knew" the author is listed as a very famous adventurer
The Book of Regrets (legendary, no attunement required)
This legendary item does not require attunement. Anyone can read this sturdy but worn tome that detects as conjuration and divination magic. It is simply emblazoned with the title "Things I Wish I Knew" and the author is a famous adventurer. No other information can be discerned through Detect Magic or Identify.
The book is always discovered in a location that was difficult to reach or find. It contains the complete and truthful answer to one or more questions. The answer will always be entirely meaningful to the author of the book, but to others it may be cryptic or clear, based on their knowledge and background.
WHILE CLOSED:
The book grants all specifically-phrased wishes made by the person who currently possesses/owns it. If ownership has not been established, the first person within 10 feet of the book to make such a specifically-phrased wish automatically claims ownership.
The specific phrase is, "I wish I knew...{something}."
The book's pages are immediately filled with an answer to the wish or wishes made. The answers are designed to be completely clear and detailed for the owner. The author's name changes to match the current owner.
After any such wishes are made, the next time the book is opened or is away from the owner's sole personal possession, it teleports 200-2000 (d20x100, ignore 1) miles away to a location that is difficult to find or reach. There is a 5% chance (1 on d20) the book is teleported to a different plane.
WHILE OPEN:
The wish is granted, as above, and the book instantly vanishes from the owner's/reader's hands, as per the teleport described above. Even an Anti-Magic Shell, Time Stop, or Wish will not prevent the book's magic from taking effect.
Next: A fine needle with a short gossamer light trail where the eye should be