Frank Miller's The Dark Knight Returns was the month's bestseller, followed by Geoff Johns's Batman: Earth One, according to Nielsen BookScan figures released to ICv2.
Eight Batman-related titles appeared in the top 20, including the classics Batman: The Killing Joke, Batman: The Long Halloween, and Batman: Hush.
The Killing Joke was one of three Alan Moore-penned books to make the top 20, along with mainstays Watchmen and V For Vendetta.
Robert Kirkman's The Walking Dead continued its slow decline from the top 20, accounting for just two spots last month. The once-dominant title is expected to resume its grip on the sector when season three of the AMC TV show debuts.
Manga maintained a presence in the chart despite slipping from five titles in July to four in August. Viz Media's Naruto Vol. 57 was the highest ranked, in at ninth.