Indescribably essential. Kevin Brownlow, the late David Gill, and their superlative production and support staff at Thames Television created the absolute apotheosis of film documentary in this series. AND, to boot, they provided undoubtedly the greatest single service ever rendered to film history in seeking out these amazing pioneers and capturing their recollections and memories, shortly before they all passed forever from the scene. I have seen this innumerable times, yet I still fall back in awe at sequences such as director Allan Dwan describing his entry into the film industry in 1911, or cameraman Karl Brown speaking of the 1915 opening night of "Birth of a Nation". I also highly recommend Brownlow's predecessor book "The Parade's Gone By" (1969), and the companion book to the series "Hollywood, the Pioneers" (out of print). Also, the subsequent Brownlow documentaries on Chaplin, Keaton, Harold Lloyd, DW Griffith, and Lon Chaney are all of equal quality, and beautifully augment original the series. I can only hope that when the DVD version of Hollywood is released, it will include unedited interviews with the participants.