In 1971, when a north-shore folk trio called Triad added an electric bassist, changed its name to Redwood Landing, and began to pepper its sets with folk rock, American popular music hadn’t developed the many polarizing categories that would define the 80s and 90s. The founding members wrote songs that ranged from blue-eyed soul to calypso to white-boy funk, and by the time they graduated from Lake Forest College in ’73 (skipping the ceremony to play a gig at Evanston’s legendary liquorless nightclub, Amazingrace), original material made up more than half their act. But the band really blossomed about a year later, when reedist Steve Eisen and wild-eyed jazz drummer Andy Potter came on board; Eisen’s tenor and flute work gave the music ballast and texture, and like a roughly contemporaneous west-coast group called Sweetwater, the Landing soon developed a seamless blend of folk, light jazz, pop, and rock–appealing to fans of every one of those idioms, even if they’d thought they couldn’t stand the others. Redwood Landing had a respectable local following throughout the 70s, and after the band broke up, the core members–vocalist and percussionist Neal Howe, bassist Ron Kaplan, and guitarists Mitch Meyerson and George Potts–reunited a few times in the early 80s, replacing Potter with versatile Chicago studio drummer Jim Hines. (Howe now lives in California, and Potts in Connecticut.) At this weekend’s 30th-anniversary bash, Hines and Eisen will join the original foursome, as will two late-period Landing alumni, keyboardist Dale Powers and Latin-percussion ace Ruben Alvarez–meaning the lineup includes almost everyone who’s ever played with the band. The celebration also marks the limited-edition reissue of the solid early-80s collection Little Joe’s Lost Tapes (available through www.redwoodlanding.com), beefed up with four in-concert tracks. The last time Redwood Landing played publicly was at the Wise Fools Pub on Lincoln Avenue in 1981–so long ago that the club has since shut down, faded into a fond memory, and then reopened at the same address. Saturday, September 8, 7:30 PM, Old Town School of Folk Music, 4544 N. Lincoln; 773-728-6000.