are beloved because they didn't fit any distinct mold. They were the first all-female rock band to be signed to a major label, inking a deal with in 1970. All-female bands existed prior to -- and not just girl groups in R&B, either; there were garage rockers -- but this quartet wasn't a throwback to the three-chord primitives that popped up after the British Invasion. No, were a self-contained rock band, the kind that seized the expansion of psychedelia to write and record their own songs. Thing was, they weren't really psychedelic, and although they could rock, they weren't heavy rockers, nor did they push at the boundaries of what constituted pop and rock. Quite the contrary, actually: they belonged to the mainstream, which is why -- who then-recently had success with and produced and would soon helm smash albums by and -- was chosen to produce their debut. He could emphasize their bright, tuneful qualities without sacrificing their backbone, and that's precisely what he does on , giving them some serious punch without ever suggesting serious rebellion. were slightly ahead of their time, not in the sense they could have run with , but in that after a few years, this kind of rocking pop could have eased onto the radio alongside "Brandy (You're a Fine Girl)," as was another band that walked the line between boogie and pop. also recall a bit of here, both in how they power through power chords and how they settle into sweetness, and that versatility is pretty appealing, while their division of songwriting duties is impressive, with guitarist and her sister writing the hardest-rocking numbers and keyboardist penning the lighter, weirder moments (exception being the nifty "Changing Horses," which hits as hard as a song). As good as these originals are -- and they are good, they're all solid songs -- 's nimble cover of 's "Badge" may explain their music best of all: they cut away the mystery of the original, straightening it out but giving it a looser, almost funky backbeat and never forgetting to jam. The album is somewhat tied to its times, but appealing for its unapologetic celebration of everything paisley, bell-bottomed, and post-hippie. ~ Stephen Thomas Erlewine