The Milwaukee Art Museum is clearly defensive about whether the stuff of its newest exhibit, "Masters of American Comics," can be considered "art." In reality, the museum didn't need to worry.

Publicity material for the exhibit, a massive collection of originals from cartoonists and comic creators, presents comics as "a bona fide cultural and aesthetic practice." Frankly, that's a lot of wordage for a medium that made words like "Zowie!" and "Kapow!" into expressive phrases.

All it takes is one look at the dreamscapes and blueprint-accurate architecture of the comic strip "Little Nemo" to convince the viewer that this is indeed art. And if that doesn't work, there's the spooky, surreal "Wee Willie Winkie's World," the kitschy 1970s "Fantastic Four" comic books, Chris Ware's off-putting geometric drawings, Gary Panter's tortured frames, Charles Schulz's "Peanuts" nostalgia-enhanced primary colors… you get the idea.

The exhibit progresses roughly chronologically, beginning with the earliest newspaper comics. Winsor McCay's "Little Nemo" (1905) is the best of the bunch. Each installment chronicles a little boy's adventures in his dreams, a set-up that gave McCay ample license to conjure the worlds of limitless fantasy seen in the exhibit, like a bed growing legs and galloping across a nocturnal cityscape.

McCay's thin, sharp lines, relatively wide color palette and attention to detail are what make these dream worlds come to life. When a panel's yellow-lit windows glow against a pale purple sky, the viewer can almost feel the descent of twilight. Furthermore, every bedstead is grooved, every window beveled, every blanket rumpled — McCay's fidelity is at times breathtaking.

In a similar vein is Lyonel Feininger's "Wee Willie Winkie's World," in which our pint-sized hero confronts chubby-faced clouds, howling trees and scowling buildings. Lest the viewer think everything from this era was the stuff of fables, there's E.C. Segar's Depression-era "Thimble Theater," which counts Popeye among its cheerfully rendered cast and George Herriman's playfully Dr. Seuss-like "Krazy Kat." The claims of these last two to the status of art are more tenuous than were those of "Little Nemo" and "Wee Willie Winkie," but are merely less technical, not necessarily less artistic.

The exhibit gets a little gummy in the middle when rock-jawed heroes and kittenish dames enter the scene. Whereas "Little Nemo"-type comics usually presented an unbroken story on an entire page, 1930's serial comic strips like Milton Caniff's "Terry and the Pirates" and Chester Gould's "Dick Tracy" more often only presented a few panes of action, which makes a single example harder to appreciate. The artists are also less attentive. They may have introduced sex appeal and violence to the comics, but the characters look frozen in place even when they're running or yelling. Rendered with thick lines, simplistic backgrounds and heavy shading instead of detail, comics of this class have pop culture value but are appreciably less imaginative than their earlier peers.

Kitsch prevailed in the '60s and '70s when comic books like Jack Kirby's "Fantastic Four" arrived to suck away fanboys' allowances. The characters are still frozen in place, but have swooping lines to indicate movement, eyes that widen from frame to frame and a sense of space and relativity.

By the end of the exhibit, only graphic novels are displayed like Art Spiegelman's "Maus" and Chris Ware's "Acme Novelty Library." It's a shame, because modern newspaper comics like "Calvin and Hobbes" have traits worthy of this exhibit. Some of the work is self-conscious — Gary Panter's "Three Acts" owes a lot more to Picasso's "Guernica" than it likes to admit — but it exposes many social quirks by using the grit of unappealing imagery or questionable subject matter.

After some stuffy past exhibits, it's good to see the museum buck its own trend and take a chance. If only it could stop pointing out that Feininger was a founding father of the Bauhuas movement and that Art Spiegelman also does covers for the New Yorker. After all, it's the capes, the colors and the comics we're here to see.