The say you should never judge a book by its cover, but Sotheby's in New York is asking you to do just that when it auctions what could end up being the world's most valuable book.

The Bay Psalm Book, the first book printed in North America, is being sold by the Old South Church in Boston to raise money for its mission and ministry, and is estimated to fetch between $15 to $30 million.

It is one of 11 surviving copies, which were printed by Puritan settlers in Cambridge, Massachusetts, in 1640, before the United States even existed.

The settlers decided to write it as they wanted a book that was a closer the original Hebrew than the one they brought over from England.

The last one to be sold at auction was in 1947. It went for a record $151,000, far more than anyone else had paid for other rare books at the time, such as the Gutenberg Bible and Shakespeare’s First Folio.

"This little book of 1640 was a precursor to Lexington and Concord, and ultimately to American political independence. The Bay Psalm Book is a mythical rarity.  Unseen on the marketplace for more than two generations, it has become too rare to collect.  Yet here it is today, this little book printed in the American wilderness but embodying the values that created our nation,” David Redden, chairman of Sotheby’s books department, said.