The first entertainment industry documentaries date back to the early 20th century, with films like "The Birth of a Nation" (1915) and "The Gold Rush" (1925) providing a glimpse into the early days of cinema. However, it wasn't until the 1960s and 1970s that documentaries about the entertainment industry began to gain popularity, with films like "Woodstock" (1970) and "The Last Waltz" (1978) showcasing the music industry.