DC Comics is enjoying a major boost in sales of Frank Miller’s “Batman: The Dark Knight Returns” now that Zack Snyder has said he’s turning to the four-part miniseries and graphic novel as inspiration for his follow up to “Man of Steel,” which will feature the caped crusader facing off against Superman on the big screen during summer 2015.

The publisher said digital sales of the graphic novel surged 161% in July, compared to June, and set a single month sales record for a full-priced DC Entertainment eBook.

The print edition showed a similar increase, according to Bookscan.

“Superman: Unchained” #2 and “Batman” #22 also were the top two selling comicbooks in July, according to Diamond Comic Distributors, the largest comicbook distributor, while “Justice League” #22, that pits three Justice League teams against each other, was the fourth bestselling title during the month.

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During Warner Bros.’ Comic-Con presentation, in San Diego, Snyder introduced “Man of Steel” actor Harry Lennix, who read from Miller’s “Dark Knight Returns,” published in 1986. The excerpt features Bruce Wayne speaking: “I want you to remember, Clark. In all the years to come. In all your most private moments. I want you to remember my hand at your throat. I want you to remember the one man who beat you.”

But the “Man of Steel” follow up will not be entirely based on the graphic novel, Snyder said. In the book, a 55-year-old Bruce Wayne ends his retirement as Batman to fight crime and aims to take down Superman. Miller’s sequel, “The Dark Knight Strikes Again,” was published in 2001.

The graphic novel already has been adapted as a two-part direct-to-homevideo title through the DC Universal Animated Original Movies banner, with the first introduced in September 2012, followed by the second in January.