Fifty years after the summer of 1969, Woodstock and Altamont remain symbols of the hope and despair generated by the counterculture. The concerts also reflected the diversity and complexity of the sounds of the Sixties. Professor Michael Flamm of Ohio Wesleyan University, author of In the Heat of the Summer: The New York Riots of 1964 and the War on Crime, explores the impact of demography and technology on the music of a generation from the British Invasion and Motown to protest songs and psychedelic rock.