The Telegraph reported the collection of works by Spanish philosopher Francisco Suarez, titled Varia Opuscula Theologica, given to the town's Oxfam book shop is over 400-years-old.
The author has been widely regarded as the founding father of international law.
The Jesuits were members of the Society of Jesus, Catholics, sent out into the world to do missionary work. From the stamp inside the book it was thought to have been originally owned by the Jesuit library in Rome, however how the book ended up in a charity shop remains unknown.
The only other clue was faint pencil marks inside the front border, including the number seven, thought to be a library number.
The shop is now selling the book for £500 through AbeBooks, a specialist service in rare editions and prints.
Paul Lister, a volunteer in the shop was tasked with tracking down records of any other existing copies. He said: "There is obviously a story behind the book, we don't know how it came to be smuggled out.
"It just came in with some antiquarian books."
This is not the first time a valuable or unusual book has turned up at the charity shop in Shrewsbury, it once sold a signed first edition of To Kill A Mockingbird for £800.
The author Franciso Suarez was ranked second to Thomas Aquinas amongst early modern philosophy scholars, he was one of the most influential theologians of the Jesuits.
Michael Walsh, the British historian of the Jesuits said the book: "May well have been in the possession of a student from the library who came to this country as a missionary."
