Chris Ware has a tendency to finish his sentences on the downbeat.

 

Maybe it's just his personality. Or maybe it's because he has worked for the last quarter of a century in an art form that's only just beginning to be taken seriously. Whatever the reason, when he speaks, his words will often trail away, stutter to a close with a deflating "... I guess" or a diminishing "... I dunno". Self-assertion is not a strongpoint.

So maybe it's time we did it for him. Ware's new book, the graphic novel Building Stories, is one of the most remarkable, thrilling and possibly important books of the year. Are we clear on that? Good.

Actually, Building Stories is more a box than a book: a container of 14 different pieces – books, pamphlets, single sheets, to be read in any order – that combine to tell the story of an apartment building and the people who live in it, one woman in particular. As a thing, it is high-end sumptuous. "As our production director put it," Ware's publisher Dan Franklin says jokingly, "the paper had to be rolled between the thighs of Chinese virgins." As a work of art it is – aw, hell, I'm just going to say it – magnificent. He sounds both flattered and embarrassed by the compliment.

Ware lives in Oak Park, Illinois, "one block west of Chicago", with his school teacher wife and seven-year-old daughter. When we speak he's sitting in his studio on a fake leather chair (bought for $89), with an almost finished pencilled page on the drawing table in front of him. He's looking out at an oak tree "that's sort of a chartreuse colour" and still tender from dental surgery the day before. It has taken him 11 years to make Building Stories ("Don't keep reminding me" he says when I bring it up a second time), though in his defence he says he's also completed 250 pages of another graphic novel. No matter; it's been worth the wait.

The idea of the box came two years into the process but it's been kicking around for a while. "The second proposal I made to my very first publisher in 1987 was to do a small box of individual tiny comics." In the past he's cited Marcel Duchamp and old comic books as inspiration for the idea. Today he mentions the artist Joseph Cornell whose art, to put it bluntly, consisted of putting found objects inside boxes.

"I think anybody who sees Joseph Cornell's artwork is immediately inspired in some way towards making art. He inspires instant affection in the viewer and I wanted hopefully to impart some small shred of that. And there's something about the vulnerability of a box of things and the promise contained in it which seems a little less masculine than a solid tome ..." He pauses, tails off. "I dunno ..."

What the "box of things" allows Ware to do as a graphic novelist is play with form. Pages are designed to be read in ways that are never just linear. Stories meander across the page, circle around central images. Ware breaks the world up into tiny and tinier panels that find their own way. Unlike so many comic artists Ware is not a camera.

"I think early on I decided rightly or wrongly that comics sort of froze up as an artistic medium approximately with the advent of sound motion pictures in 1930s and 1940s. The genre in America solidified into this kind of adventure storytelling, and it wasn't until the 1960s, with cartoonists like Robert Crumb and Kim Deitch and Art Spiegelman, that they reinvented comics as a medium for actual human self-expression. There are other ways of getting at a sense of reality that had more to do with comics than the idea of a camera. Because comics are an inwardly turned thing. It's really a way of getting your memories out on the page. It's almost a way of making dreams real."

This is key to the success of Building Stories. The formal inventiveness has an end. It's a "novel" about memory, about time passing, about the small sadnesses of the everyday, about the catalogue of losses that accrue simply from being alive. It's about old boyfriends, parents, all the people who fade from us. Reading it, I felt my heart was being dropped on a hard stone floor from a great height. Repeatedly. Years pass between panels. Stories jump forward and back in the spaces in between. Reading Building Stories, you realise that no art form – not one – is more capable at conjuring so effortlessly, so painfully, the slippage of time.

Ware says it's about paying attention. He reckons we don't do that any more. "I think people 100 years ago saw the world better than we see the world. We're so used to not really looking at anything any more. We get out of the way of things heading towards us but that's really about all we do. We look but we don't see. I think 100 years ago people saw the texture of life that much more finely. You look at newspapers from 100 years ago, and the type is so small it's almost unreadable to our eyes."

And comics are one way of getting back to that way of seeing. "We reduce the world to visual templates and then turn that around and use it as a way for telling stories and hopefully getting in a sense of the freshness of the world that we had when we were children."

That's what Ware is doing here. Making the world box-fresh.

Building Stories is published by Jonathan Cape, priced £30