William Powell was a teenager, angry at the government and the Vietnam War, when he walked into the main branch of the New York Public Library in Manhattan in 1969 to begin research for a handbook on causing violent mayhem.

Over the next months, he studied military manuals and other publications that taught him the essentials of do-it-yourself warfare, including how to make dynamite, how to convert a shotgun into a grenade launcher and how to blow up a bridge.

What emerged was “The Anarchist Cookbook,” a diagram- and recipe-filled manifesto that is believed to have been used as a source in heinous acts of violence since its publication in 1971, most notably the killings of 12 students and one teacher in 1999 at Columbine High School in Littleton, Colo.

Throughout his manual, Mr. Powell fashioned a knowing voice that suggested broad experience in warfare, sabotage or black ops, mixed with an extremist’s anti-establishment worldview.