L7 are arguably the most important female hard-rock group ever, and with Slap-Happy, the band's seventh disc in 11 years, Donita Sparks, Suzi Gardner, and Dee Plakas show exactly why this is the case. Pounding out huge riffs with evil intensity and shrewd humor, the women of L7 practice the art of rock with a subtle intelligence that keeps their music from slipping into self-parody. On loud, boisterous songs like "Mantra Down" and "War With You," L7's notorious punk-metal roots are exposed to full, breakneck effect. With Sparks and Gardner trading vocals and meat-cleaver guitar breaks while Plakas beats the holy hell out of the drums, L7 transcend all preconceptions of gender-specific behavior and rock more aggressively than most male-led groups you're apt to mention. --Mitch Myers