Gary Miller (born September 15, 1958), better known by his stage name Dr. Know, is an American musician, who rose to prominence as the guitarist for the Washington D.C. hardcore punk band Bad Brains, who were critically acclaimed for their innovative musical style and are regarded as one of the greatest and most influential punk rock bands of all time.

Critic Rick Anderson praises Miller's "ability to meld the raw directness of hardcore punk with an almost supernatural virtuosity without sacrificing the power of either approach".

In early 2010, he made an appearance at the Trocadero in Philadelphia, PA, playing two songs with students from Paul Green's School of Rock Music at the Best of Season show.

After nearly three months in the hospital, he was transferred to a medical rehabilitation facility for the physical therapy and treatment that he needed to make a full recovery.

[4] In 2016, Miller formed the supergroup Saudade along with singer and guitarist Chino Moreno of Deftones, Team Sleep, Palms, and Crosses; jazz keyboardist John Medeski of Medeski Martin & Wood; bassist Chuck Doom, co-member of Crosses and Team Sleep; guitarist David Torn; and drummer Mackie Jayson of Cro-Mags and Bad Brains.