Literary graphic novels now have their own storefront app, thanks to Sequential, which just launched in the U.S. and worldwide after debuting in the U.K. in May. Created by Japan-based software developer Russell Willis, the app—available now for iOS but later in the year for Android—aims to offer a range of titles that appeal to readers of books like Fun Home and Persepolis.

It’s a niche that was lacking until now, says Willis, who also own the software company iEnglish. While digital comics have become a huge force in the international comics market, most providers offer a mix of periodical comics and graphic novels. Readers who aren’t familiar with the vast world of monthly comics and superheroes may have a hard time finding more “sophisticated” graphic novels that appeal to them.

To fix that, Sequential is launching with titles from U.K. publishers Blank Slate Books, Myriad Editions, Great Beast, Tabella, and Knockabout—SelfMadeHero and Walker Books are also in the pipeline, Willis told PW, along with Jonathan Cape, publisher of award-winning authors Posey Simmonds and Raymond Briggs.

He's negotiating now with U.S. publishers. Books sell for between $4.99 and $9.99. Willis estimates the size of market for non-superhero graphic novels as between $50 and $75 million—and thinks offering them digitally will be a way to expand the audience even more.

Books are available now from such well-known authors as Alan Moore, David Lloyd (V for Vendetta), Brian Bolland (The Killing Joke), Eddie Campbell (From Hell), Hunt Emerson, Hannah Eaton and more.

Sequential’s parent company is Panel Nine, also owned by Willis, which kicked off about a year ago offering out of print graphic novels as standalone apps—including Campbell’s Dapper John and David Lloyd’s Kickback. Although the individual books sold, Willis wanted to create a store where related material was more discoverable.

Sequential offers its comics in its own proprietary formats: “Panel Mode” offers a one panel at a time reading experience, while “Sequential Mode” offers more slideshow effects. These join Comixology’s well-known “Guided View” and Amazon’s own “Panel View” as different methods of transferring a page to digital—all of which can offer additional storytelling devices. Some releases will offer DVD-like extra features; for instance, Kickback includes an audio track by creator David Lloyd, as well as extra sketches and covers.

While selling existing publishers books is the focus for now, Sequential will eventually offer more out-of-print graphic novels via Panel Nine.