MIMBRES POTTERY: ANCIENT ART OF THE AMERICAN SOUTHWEST with essays by J. J. Brody, Catherine J. Scott and Steven A. LeBlanc and introduction by Tony Berlant (Hudson Hills: $15.95, paperback). The Southwest Museum's current exhibition of Mimbres pottery--the sleeper show of Los Angeles' summer art season--has been extended to Oct. 13, but local devotees of Southwestern art are still dreading the departure of the enchanting display of fanciful draftsmanship. The handsome, profusely illustrated catalogue serves as a permanent record of the temporary event and as an authoritative guide to those who would learn what little is to be known about the art of a tribe that vanished about 1,000 years ago. Mimbres ceramics evolved, over 900 years, from plain brown ware to masterful abstraction, reaching its zenith in the black-and-white figurative painting that so astonishes today's audience. The Mimbres did not just decorate pottery; they used clay forms as canvas to portray their world as "an amiable cosmic circus," in Berlant's words. They painted themselves and an array of animals swirling in panoramic hemispheres. Many of these painted bowls were then ritually "killed" with punctures and put on heads of the departed. Bulldozers have claimed most of the Mimbres' creations, but enough remains to prove their artistic brilliance.