During the twenty-seven years bounded by the Mexican and Modoc wars, invading white Americans ruthlessly conquered the approximately fifty California Indian tribes that had eluded Spanish, Mexican, or Russian domination. Triggered by US annexation and the subsequent gold rush, the final subjugation of Native California resulted in a shocking demographic collapse that slashed the state’s Indian population from an estimated 150,000 in 1845 to a mere 30,000 by 1870. Although demographer Sherburne Cook carefully calculated that epidemic diseases caused fully 60 percent of this loss and that lethal violence accounted for less than 4 percent, historian Benjamin Madley argues that the “California Indian catastrophe” was no accidental tragedy but rather a clear-cut case of “genocide as defined by the 1948 UN Genocide Convention” (14).To prove his case, Madley has produced a towering book that will long endure as a landmark text in California history. Among its many achievements, this painstakingly researched and thoroughly documented work provides by far the most complete and detailed account ever written about the murderous campaigns waged against Native peoples by the US Army, the California state militia, local volunteer militia units, and irregular bands of self-appointed “Indian fighters.” Grimly, and relentlessly, Madley’s 360-page narrative “focuses on documenting and analyzing deaths due to direct acts of violence” and, in so doing, “reveals many of California’s so-called Indian wars for what they were: genocide campaigns that California Indians violently resisted” (11–12). Determined to let no killing escape the historical record, Madley bolsters his argument with eight appendixes spanning 194 pages. With encyclopedic detail Madley tabulates every murder, battle, and massacre uncovered by his years of research in the primary sources and lists each army, militia, and vigilante expedition as well. According to Madley’s meticulous count, these invariably one-sided encounters claimed the lives of “at least 9,492 to 16,094 California Indians” between 1846 and 1873. As Madley points out, “This more than doubles Cook’s calculation of 4,556 California Indians killed between 1847 and 1865” (12).But did all these terrible killings, spread out across a vast territory and over the course of a quarter century, really add up to a single “American genocide” perpetrated by a “killing machine” built, sanctioned, and funded by politicians and lawmakers in both Sacramento and Washington (13)? Critics will raise at least four objections. First, Madley’s attempt to link so many separate events into a genocidal whole relies on a largely circumstantial and contextual argument that, in turn, depends heavily on the UN Convention’s overly broad and elastic definition of genocide. Consequently, the numerous scholars who reject the UN standard will likely dispute Madley’s overall interpretation.Second, Madley’s analysis does not actually cover all of Native California, since he declines to measure the Spanish or Mexicans by the UN yardstick, and, except for the Cupeño and Wappo, does not examine the post-1846 fate of the numerous tribes that had fallen under earlier colonial rule. Third, the strength of Madley’s evidence for genocide varies considerably from place to place and is far stronger in some cases (such as the army’s slaughter of the Pomo at Clear Lake and Cokadjal in 1850) than it is in others (such as the Modoc War of 1872–73). Similarly, in regard to the respective guilt and complicity of the various alleged perpetrators, the proof offered against the US federal government is not nearly so strong as the damning evidence Madley compiles against the frontier miners, farmers, and ranchers who took so readily to exterminatory “warfare.”Fourth, while Madley’s tally of killings is more than twice that of Cook’s, epidemics, not violence, still remained by far the greater factor in Native mortality, a fact that Madley acknowledges but never squarely confronts, tending instead to submerge the role of disease beneath his thick descriptions of mayhem.Nevertheless, Madley’s case for genocide is overwhelming and compelling in many specific instances. As his evidence makes plain, deliberately exterminatory campaigns devastated at least eighteen California tribes, including the Achumawi, Karuk, Lassik, Nisenan, Nongatl, Owens Valley Paiute, Pomo, Shasta, Sinkyone, Tolowa, Wailaki, Wappo, Whilkut, Wintu, Wiyot, Yana, Yuki, and Yurok.Beyond the shadow of any reasonable doubt (and by the standards of any reasonable definition), genocide did in fact play a significant role in the US conquest and subjugation of Native California.