"As cyber-attacks dominate front-page news, as hackers displace terrorists on the list of global threats, and as top generals warn of a coming cyber war, few books are more timely and enlightening than Dark Territory: The Secret History of Cyber War, by Slate columnist and Pulitzer Prize-winning journalist Fred Kaplan. Kaplan probes the inner corridors of the National Security Agency, the beyond-top-secret cyber units in the Pentagon, the "information...