Two of the most coveted Batman comics - including one that shaped the modern day perception of the hero - will go under the hammer in Dallas next month.
The 1986 Dark Knight Returns No.2 cover is expected to fetch more than $500,000 (£335,638) while a copy of Batman No.2 from 1940 should sell for $850,000 (£570,584).
The Dark Knight pen and ink creation - drawn by writer and artist Frank Miller - captured the grim visage of an older, wiser, meaner Batman.
Heritage Auctions, which will sell the comic, said Miller's story "radically altered the direction of the comics".
It is the first cover from DC Comics' 1986 four-issue "Dark Knight" mini-series to be sold.
Todd Hignite, Heritage's vice president, said: "For fans of modern comics, this drawing is where everything really begins.
"This moment defines Miller's Dark Knight, and the modern day perception of Batman, like no other drawing."
The only cover Mr Hignite says might come close is the next in the series - with Batman and Robin - that was auctioned two years ago for nearly $450,000 (£302,000).
He said: "It represents not only one of the most memorable images from the 1980s, but from Batman's entire illustrious history.
"Miller's revolutionary Dark Knight radically altered the direction of comics with its prestige miniseries format, combined with the fact that it was one of the first modern mainstream features to put a gritty noir patina on the squeaky-clean Silver Age hero mythos previously exemplified by DC."
Also up for sale is a 9.2-graded copy of Batman No.1 that shows Batman and Robin swinging in front of a Gotham City skyline.
It is being auctioned on behalf of Tadano America Corp. A similar copy sold for $850,000 (£570,000) in 2012.
Barry Sandoval, director of operations for comics and comic art category at Heritage, said: "By any measure this is one of the most desirable comic books in existence.
