An art book bought for $80 (£52) has been found to contain four original Picasso works.
The worth of the prints was a chance discovery
Brett Floyd, 39, bought the book, Picasso: Toreros, at a California fundraising event a year ago.
Then one month ago, the art lover noticed a framed lithograph in a gallery identical to one in his folio.
He has since had the book valued at $17,000 (£11,000).
The mortgage broker from Tustin Ranch bought the 1961 book at a silent auction for the Friends of the Tustin Library.
He was oblivious to what he had really purchased until he went to a gallery in Newport Beach months later.
Mr Floyd told BBC News: "About a month ago, I was walking into a gallery and I saw one of these lithographs which is in this book.
"That's when the whole thing unravelled."
The gallery's art consultant told him the sketch on the wall was taken from the 1961 book.
And Mr Floyd then discovered there were four originals in the folio and had them valued.
Mr Floyd hopes to make $25,000 at auction
He intends to take the volume to Christie's in Beverly Hills for auction, where he thinks they can make £25,000 (£16,000)
But he plans to donate 10% of the cash to the Friends of the Tustin Library.
Chris Brickley, of Bonham Auctioneers in the UK, said: "Picasso had a career of 70 years plus and was a major creative force.
"He was constantly sketching and drawing anywhere, in sketch books, envelopes, postcards, anything he could get his hands on.
"So for things to turn up is not really that unusual."