For example:
* Which Harry Potter book? (e.g. "Harry Potter and the Sorcerer's Stone", "Harry Potter and the Chamber of Secrets", etc.)
* What condition is the book in? (e.g. pristine, good, fair, etc.)
* Is it a first edition, first printing? (This is the most valuable type)
* Does it have any other special features? (e.g. dust jacket, signed by J.K. Rowling, etc.)
Once you provide more details, I can give you a more accurate estimate of its value.
Important Note: Determining the true value of a rare book requires expert evaluation. Consider consulting a professional appraiser for an accurate assessment.