Thousands of music lovers are expected to converge on Old Pool Farm in Upper Salford Township, near bucolic Schwenksville, Pennsylvania, Aug. 17-20, for the annual Philadelphia Folk Festival. Now in its 56th year, the event, produced and presented by the Philadelphia Folksong Society, a nonprofit arts organization, is the longest continuously running outdoor music festival of its kind in North America. [To continue reading this article, click on the headline.]