Barton Lee Hazlewood was an American country and pop singer, songwriter, and record producer, most widely known for his work with guitarist Duane Eddy during the late 1950s and singer Nancy Sinatra in the 1960s and 1970s. His collaborations with Sinatra as well as his solo output in the late 1960s and early 1970s have been praised as an essential contribution to a sound often described as "cowboy psychedelia" or "saccharine underground". Rolling Stone ranked Lee Hazlewood & Nancy Sinatra No. 9 on its list of the 20 Greatest Duos of All Time.