Easy listening music is a style of popular music an radio format that emerged in the mid-20th century, evolving out of swing and big band music, and related to Beautiful music and Light music. Easy listening music features simple, catchy melodies, soft, laid-back songs and occasionally rhythms suitable for couples dancing. The genre includes both instrumental forms (often played on light of tone instruments such as the Hammond Organ, "lush strings", or Ukulele); and vocal forms featuring pop singers, such as Barbra Streisand, Perry Como, Andy Williams, Jack Jones, Engelbert Humperdinck, Eydie Gorme, Barry Manilow, Harry Connick Jr., Frank Sinatra, Johnny Mathis, Bing Crosby, Tom Jones and Mel Tormé. Exotica music stylists such as Les Baxter and Martin Denny are often included within the purview of easy listening music as well.