Book excerpt: The Scopes Monkey Trial, the Sacco and Vanzetti case, Brown v the Board of Education, and even subsequent televised high profile murder trials pale in comparison to Arizona v California, argues author Jack August in Dividing Western Waters, August’s look at Arizona’s Herculean legal and political battle for an equitable share of the Colorado River. To this day Arizona v California is still influential. By the time Mark Wilmer settled in the Salt River Valley in the early 1930s, he realized that four basic commodities made possible civilization in the arid West: land, air, sunshine, and water. For Arizona, the seminal water case, Arizona v California, the longest Supreme Court case in American history (1952–1963), constituted an important step in the construction of the Central Arizona Project (CAP), a plan crucial for the development of Arizona’s economic livelihood. The unique qualities of water framed Wilmer’s role in the history of the arid Southwest and defined his towering professional career. Wilmer’s analysis of the Supreme Court case caused him to change legal tactics and, in so doing, he changed the course of the history of the American West.