Thank you for contacting Mearto with your appraisal inquiry. Based on the photographs and description provided, the subject of this appraisal is a non-authenticated "Concept of Worship in Islam" pamphlet bearing a signature in blue ballpoint pen of boxing legend Muhammad Ali, with an inscription of "To Jackie from Muhammad Ali 1-26-89". According to the current owner, the piece was acquired from Ali first-hand in an airport.

The market for genuine Ali autographs is high, but any unauthenticated Ali autograph should carry a conditional classification due to the amount of forgeries that are available, even when the autograph does appear quite legitimate as this one does. A reputable third-party authentication service such as PSA could verify the signature if submitted to them for examination.

As for comparable sales, a similar pamphlet sold by Heritage Auctions in 2016 for $191.20, and a pair in 2019 sold for $312.00.

In consideration of the factors noted, a Fair Market Value (pre-auction estimate) of this piece conditional upon autograph authentication by a reputable third-party authenticator would be estimated at $150 to $200.