Hopalong Cassidy #3: Hopalong Cassidy

The second book written about Hoppy, but third if you want read the series in chronological order. The events of BAR-20 DAYS (1911) precede this. Montana Ranchers move into the H2, a ranch that borders the BAR-20. A range war develops over land use and water rights. An organized gang of rustlers take advantage of the range war to clean out both ranches. Hoppy and the BAR-20 boys are just the men to stop it, but a woman from the H2 causes big complications.