On the most visceral level, polygamy is a question of human mating behaviour and when or if it's anyone's business, the author of a new book on the subject said Thursday.

As a result, the subject matter is fascinating not only to him but the public at large, said Craig Jones, a professor with Thompson Rivers University's Faculty of Law.

His book, A Cruel Arithmetic: Inside the Case Against Polygamy, launched earlier this week. Jones will do a reading Wednesday, Oct. 10, at the downtown library at 7 p.m.

Jones was part of a small team of lawyers from the federal and provincial governments who led a constitutional challenge against polygamy in the B.C. Supreme Court.

The case became known as the Polygamy Reference and took place during 44 days from 2009 to 2011. An exploration of life in the community of Bountiful, the case included more than 100 witnesses — many of whom offered stark and disturbing confessions under a shield of anonymity.

During the case, almost everyone Jones had a conversation with — be they baristas at Starbucks or university professors — was interested in and knowledgeable about the subject matter.

"Everyone had a pretty good grasp on the issues and kind of a nuanced understanding of the whole idea of the collision between civil liberties and religious freedom and legitimate state interest," Jones told The Daily News.

"It was fascinating to me how sophisticated the thoughts were on the subject from the people I met. I'd never had that before."

The show of public interest prompted Jones to write a book about the case, Bountiful and the suggestion by psychologists, anthropologists and historians that polygamy is as natural a human behaviour as monogamy.

In one chapter, Jones uses champion golfer Tiger Woods and U.S. politician Newt Gingrich as examples of married men who practise what he calls alternative mating strategies.

Woods had a number of mistresses, each of which he had a low level of emotional investment, said Jones. Gingrich has had three wives, all of them younger than the one who came before. And, he points out, there was an overlap between relationships.

"Anthropologists or psychologists would call that de-facto polygamy. That we're not monogamists in the strict sense of mating once per life," he said.

"We've established a kind of kinder, gentler form of polygamy where we ensure that the children of successive unions are cared for."

The title, A Cruel Arithmetic, is reflective of how the Bountiful wives became younger and younger with each passing decade, he said. As more women became married off, the number of older women dwindled and men turned to younger partners.

A Cruel Arithmetic is for sale at Bookies at TRU or online at www.irwinlaw.com and chapters.indigo.ca.