The author of “The Anarchist Cookbook,” a manual for causing violence which has sold millions of copies, has died at the age of 66.

William Powell began his researching his book in the wake of his anger as a teenager about the Vietnam War.

The result was what the New York Times called “a diagram- and recipe-filled manifesto” that Mr Powell saw as an “educational service for the silent majority.”

Mr Powell died on 11 July 2016 however media was not aware of his passing until the recent documentary, called “American Anarchist,” was released by director Charlie Siskel.

He was born in 1949 on Long Island and lived in England for some time due to his father’s work as a United Nations spokesperson.

It is believed that the book was used by high school students when they killed 12 fellow students and a teacher in the 1999 Columbine High School shooting incident in Littleton, Colorado.

The Washington Post reports that the manual was also used by Timothy McVeigh in the 1995 Oklahoma City bombing that killed 168 people including children in the government building’s daycare as well as the 2001 shooting in Tuscon, Arizona that severely injured Congresswoman Gabrielle Giffords.

Mr Powell wrote in the book that revolutionaries believe “that the government in power is illegal...I see no reason that he should feel restricted by laws made by an illegal body.”

He saw himself and his colleagues as challenging the authority of then-President Richard Nixon.

In “Anarchist Cookbook” Mr Powell covered topics like how to set booby traps, build explosives, sabotage, drug use, and combat methods.

Later in life, however, Mr Powell expressed regret at the way the manual was being used, saying it was a “misguided product of my adolescent anger at the prospect of being drafted and sent to Vietnam to fight in a war that I did not believe in.”