Books Briefly -- Gringos By Adam Woog [ A review of Gringos, by Charles Portis, Transcribed by Alex T. Moore from The Seattle Times (March 3, 1991), for non-commercial use on The Unofficial Charles Portis Website (http://charlesportis.cjb.net). ] Charles Portis is a comic writer from Arkansas best known for "True Grit," which became a John Wayne movie that was very different from - and not nearly as good as - the novel. Portis has been a kind of secret weapon in Southern-humorist circles for a long time, although he's not prolific (only five novels in 25 years), and many of his fans felt his last book, "Masters of Atlantis," was one long slip on a big banana peel. (Portis' editors apparently feel the same way; the jacket copy for "Gringos" says that "Portis is back again at the top of his form.") "Gringos" is, indeed, a return to the old Portis whimsy. Jimmy Burns is a ratty American expatriate, eking out a living with a small truck in small-town Yucatan. He's very good at observing and judging the other nutty outcasts, American and otherwise, who wash up in the area. Among them are a pompous flying-saucer buff and his headstrong wife; self- absorbed hangers-on around archaeological excavations; and a loony bunch of hippies (as Burns grumpily still insists on calling them) who steal car parts and worship Mayan ruins. Burns is no paragon himself - he has his own demons, including the fact that no one will believe he doesn't trade in black-market artifacts anymore. Among its other merits, "Gringos" is a wonderfully trenchant, bittersweet treatment of the bizarre way expatriates justify their marginal existences. This isn't belly-laugh slapstick, but if you can get past the leisurely start - the pace is, shall we say, measured - Portis' casual charm is addictive. He's ingratiating without being corny, his tone is both cool and warm, and his characters are so amiably off-center that you can overlook the fact that the plot seems almost an afterthought.