Robert "Bob" Hartman (born December 26, 1949) is a Christian artist, guitarist, writer and songwriter. He is the founder of Christian rock band Petra. Hartman was involved with the band from its foundation in 1972 to its end in 2005. He took a break from touring in 1995, but continued to write most of the band's songs, record guitars and produce most of the albums. He officially returned to touring with Petra in 2003 until he decided to retire the band in late 2005.