How a bunch of swashbuckling tech bros upended the way America fights its wars

At 11:16 a.m.local time on Sept.

28, 2008, operating from the Kwajalein Atoll in the central Pacific Ocean, the Space Exploration Technologies Corporation — a privately-funded company, founded by a 37-year-old South African emigree named Elon Musk and headquartered in Hawthorne, Calif.— launched a rocket of its own design, Falcon 1, that reached low orbit nine-and-a-half minutes later.This marked one of the great dividing lines in human history.

As Sharon Weinberger writes in Valley of Death: How Big Tech is Fueling the Future of War, Musk had “proved that space technology and exploration, a feat once limited to nation-states, can be accomplished with private money.” Within two decades, Axios was describing SpaceX as “the most valuable defense contractor in the world.”A veteran national-security reporter for outlets such as Aerospace Daily and The Wall Street Journal, Weinberger, has enjoyed privileged access to both worlds whose convergence she chronicles in “Valley of Death”: tech and defense.She was inside the Pentagon when al Qaeda struck on Sept.11, 2001, and has visited all the gleaming tech campuses.

The reporting in this book benefits from access to all the major players, sometimes top officials or executives speaking anonymously; previously unpublished documents from military and Silicon Valley sources; and firsthand accounts from important scenes and events.In the modern literature devoted to the nexus between the defense establishment and private industry, a genre that might be traced to William Manchester’s “The Arms of Krupp” (1965), “Valley of Death” is the most up-to-date entry, a landmark of research and synthesis.Few other subjects are of greater moment: With each passing second, artificial intelligence refashions human existence.Nor can we forget the awesome power of this nexus, which helped produce two other of human history’s great dividing lines: the destruction of whole cities by atomic weapons, which defeated fa...