I have really enjoyed the Aurum books on Science Fiction and Gangster movies, and though Westerns are far lower on my cinematic ladder of lust than the two aforementioned genres, I certainly enjoy the well-made ones, and would most definitely love to find more to investigate. Its introduction ('The Western in Perspective') is in four parts: 'What's in a Name?', 'America and History', 'Heroes and Villains' and 'Hollywood and the Western'. Hit 'Read Notes' for more info from this tome...and I hope you enjoy.
The Thirties: 1-403, plus 61 films below = 464 films (26.07%)
'The Rise and Rise of the B Western'
The Forties: 404-817, plus two films below = 416 films (23.37%)
'The Resurgence of the Genre'