American Hardcore Punk band formed in Washington, D.C. in 1977, initially as a jazz fusion ensemble called Mind Power.
The band also do many reggae and dub tracks and featured elements from funk, heavy metal or hip hop.

Classic line-up:
H.R. (Paul D. Hudson) — lead vocals (1978–1987, 1989–1990, 1994–1995, 1998–present), guitar (1977–1978)
Dr. Know (Gary Miller) — guitar (1977–1995, 1998–present)
Darryl Jenifer — bass (1977–1995, 1998–present)
Earl Hudson — drums, percussion (1977–1987, 1989–1990, 1994–1995, 1998–present)

The original line up broke up many times and some musicians replaced H.R. and Earl Hudson:
Sid McCray — lead vocals (1977–1978)
Taj Singleton — lead vocals (1988–1989)
Chuck Mosley — lead vocals (1990–1991)
Israel Joseph-I — lead vocals (1991–1994, 2008)
Mackie Jayson — drums, percussion (1988-1989, 1990-1993)
Chuck Treece — drums, percussion (1994)