American kids of the 1970s may have been the first generation to grow up with unfettered access to cheap drugs, but it's clear that for a cadre of budding writers, the high of choice was to be found between the covers of comic books. The conflicts of the Fantastic Four helped to animate Rick Moody's ''The Ice Storm;'' Michael Chabon's Pulitzer winner ''The Amazing Adventures of Kavalier & Clay'' explored a vast swath of 20th-century history through superheroes and the men who created them; and now Jonathan Lethem, with an ambitiously scaled novel that takes its title from the sanctuary to which Superman flies off to brood, has opened his own dusty trunk of collectibles in search of inspiration.
He's found it. The good news for fans of Lethem's justly adored 1999 breakthrough, ''Motherless Brooklyn,'' is that he's followed it with a stunner -- a flawlessly evoked, original, and vividly imagined (or is it remembered?) account of two boys, white and black, growing up in not-yet-gentrified Brooklyn in a decade of both freedom and urban rot. Quiet, watchful Dylan Ebdus is a white kid whose brassy flake of a mom splits early on, leaving him with a distant, ingrown dad and one real friend -- Mingus Rude, nascent graffiti artist and son of a minor soul singer gone to seed. Their relationship starts with street-side ball games -- and comics. Casting a clarifying light into every corner of a rough-edged childhood in a rough-edged neighborhood, Lethem follows the kids from ages 6 to 18, tracing race relations, the roots of hip-hop, and the devastation of a growing drug culture through their uneasy kinship. And though this generous and deeply empathetic novelist loves his characters, he spares them nothing.
The bad news is that while said terrific novel ends on page 294, ''The Fortress of Solitude'' does not. The final 200 pages maunder, deflate, and stumble through time. An interstitial section of liner notes by the adult Dylan, now a mopey music-head whose first-person voice assumes narrative control, is a show-offy ''McSweeney'''s-esque gimmick that portends many more disappointing decisions. Suddenly, Lethem's seeming desire to write his Big Book -- to have each page billow with his definitive take on Brooklyn and race and music and drugs and boyhood -- gallops away with the discipline and specificity of his storytelling. And when Lethem indulges his taste for comic-book heroics and lets Dylan and Mingus fly off in unexpected directions, it's a daring literary gamble -- and a bad one. Still, a great novel that doesn't know when to quit is not only better than none, it's better than most merely good ones. And as long as ''Fortress'' stays earthbound, it soars.