His last published work was a 35,000-word "manifesto" that explained the motivation behind the 17-year terrorist campaign that made him one of America's most wanted men.

Now, Unabomber Ted Kaczynski has decided to release his first book. Compiled largely in his cell at a maximum-security prison at Colorado, Technological Slavery explains the philosophy behind Kaczynski's attempts to destroy western civilisation.

The strangely coherent text was co-authored by David Skrbina, a professor at the University of Michigan who has for several years taught classes on the Unabomber 'manifesto' as part of an undergraduate course on the philosophy of technology.

It contains a collection of essays and correspondence with academics in which Kaczynski expands on the beliefs that inspired his campaign: namely that, to quote one passage, "the Industrial Revolution and its consequences have been a disaster for the human race" and that technological advances are destroying the planet and eroding human freedoms.

Skrbina said that, far from being the paranoid ravings of a madman, the book is meticulously authored. "It makes logical, clear, solid arguments," he says. "I haven't met the man face-to-face – all our contact has been via letters – but in our dealings there's been no sign of mental illness. He's lucid, rational and calm."

That is a different conclusion from the one reached by court psychiatrists after the FBI arrested Kaczynski at a remote cabin in Montana in 1996. They decided he was a paranoid schizophrenic but was fit to stand trial for murder.

Kaczynski's campaign of violence, in which he killed three people and injured more than 20, started in 1978. A former academic, he was apparently upset by the destruction of the natural world, and began sending pipe bombs to staff at airlines, university professors, and the owners of computer shops. His final two victims, both of whom were killed, were Thomas Mosser, who made adverts for Exxon, and Gilbert Murray, a lobbyist for the timber industry.

The attacks ended in 1995, when Kaczynski's manifesto was published by the New York Times and Washington Post. He had promised investigators, via anonymous letters, that he would stop the bombings if the document was printed.

The publication of the manifesto led to Kaczynski's arrest: his style of writing was recognised by his brother David, who contacted the FBI. In a plea bargain, Kaczynski was spared the death penalty but jailed for life without parole.

An updated version of the manifesto is included in Technological Slavery. According to Skrbina, it provides a insight into the sort of ethical codes that terrorists use to justify their campaigns.

"I try to separate his crimes from his academic arguments," says Skrbina. "I'm interested in philosophy. I certainly don't endorse the murders he committed, but if you are studying ethics it's important to realise that there are many instances in which an individual can say there is an ethically justified basis for killing. Governments are effectively arguing that killing is justified whenever they start a war."