In less than a month, the TV show "Breaking Bad" will return to AMC for its final eight episodes. Fans of the critically-acclaimed drama have been waiting almost a year to catch up with up the story of Walter White — played by Bryan Cranston — a mild-mannered high school chemistry teacher turned ruthless meth kingpin.

Walter White is part of a growing number of antiheroes populating the TV universe since the late 1990s, from Tony Soprano to Don Draper.

This so-called Golden era of television came about as a result of network and cable companies looking for riskier, brand-defining content.

“In order to exist in a world in which where there are literally hundreds of thousands of options, a network, a station needs, more than anything, an identity – needs a brand,” said Brett Martin, who chronicles these characters in his new book "Difficult Men: Behind the Scenes of a Creative Revolution."

Martin says it was "The Sopranos" that really brought this idea together when Tony Soprano killed a man with his bare hands in an unwavering one-shot scene.

“There are some changes that happen that are so radical and so transformative that once it happens, you can hardly believe it was controversial,” Martin says.

That scene opened the gates to all kinds of behavior that viewers were willing to accept in a television hero, Martin adds. Behind every one of these unconventional heroes, is a writer or show runner who brings their own unique intensity and baggage, and is essentially the keeper of the vision.

“What they all share is a fierce vision, and the most kind and least difficult show runner is still going to be a fierce protector of his or her show, and is going to fight for it and has a sense of where this whole universe is going,” Martin said.

Nuran Alteir contributed to this web segment.