Photographs showing John and Jackie Kennedy on holiday with friends and family in Cape Cod in 1961 are due to cross the block at RR Auction on February 19.
The archive is titled: "The President of the USA and Mrs. Kennedy taken at Mrs. Melon [sic] in Mass. (Cotuit), Aug. 1961, Photos by Mrs. Graham."
The Kennedys stayed with friends at the Mellon Estate, home of Bunny Mellon - designer of the White House rose garden. The images show them in a relaxed light, clearly at ease away from the prying eyes of the media.
Author Pamela Keogh told People Magazine: "They're amazing pictures.
"These were the masters of the universe in their downtime, sitting on beach chairs, smoking and eating clam chowder.
"[JFK] is not in perfect shape and Jackie's wearing a bathing suit your mother might have worn. This is not Jackie in French couture. They don't even look like they know they were being photographed."
Bidding on the lot will start at $300, a figure it is likely to exceed substantially. A set of negatives from the Kennedys' wedding sold for $34,000 at RR Auction last year.
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