At 75, the great Chicago blues guitarist is as busy as ever. President Obama invited him to the White House last week to celebrate the blues and Black History Month for a concert, taped for PBS broadcast Monday, featuring B.B. King, Keb Mo, Trombone Shorty, Gary Clarke Jr., Mick Jagger and Jeff Beck. Guy will publish his autobiography, "When I Left Home," in May. In concert, he remains an electrifying showman, with periodic flashes of guitar virtuosity. Guy has a tendency to dismiss some of his blues chestnuts with abbreviated versions but he gets excited about paying tribute to John Lee Hooker, Jimi Hendrix and Eric Clapton, Guy's most famous disciple. Guy also is generous with stage time for his 12-year-old protégé, Quinn Sullivan, who opens.