'I'm going to camp out on the land ... try and get my soul free'. So sang Joni Mitchell in 1970 on 'Woodstock'. But Woodstock is only the tip of the iceberg. Popular music festivals are one of the strikingly successful and enduring features of seasonal popular cultural consumption for young people and older generations of enthusiasts. From pop and rock to folk, jazz and techno, under stars and canvas, dancing in the streets and in the mud, the pleasures...