"I just think 'Supernatural' is one of the most difficult shows that anyone's directed," writer, producer, and director Eric Kripke muses about his time working on the horror-drama he created for The CW which is currently in its eighth season. The near decade of Sam and Dean Winchester's adventures have taken them up against ghosts, vampires, demons, the Devil, angels, and everything in between, all chronicled in "The Essential Supernatural: On the Road With Sam And Dean," a 192-page hardcover from Insight Editions published last month.

Kripke, who provided the foreward to the current edition of the essential guide, was on-hand to talk about the history of the series and putting it all together into an "all-inclusive collection of really everything 'Supernatural.'"

Although writer-turned showrunner Jeremy Carver is at the head of "Supernatural," Kripke says the series is still his "first child." Looking back on the five years he spent in the day-to-day operations of the show, he's amazed at how much they were able to get away with on the CW show. Touching on issues of faith, life, death, and the end of the world--although that wasn't the original idea for the series. Kripke says the show initial started off as one part "Evil Dead," another part "An American Werewolf In London" with the idea being that "Supernatural" would simply be a gory horror series. He credits working with writer Bobby Singer who we says nudged him towards pushing towards more character-focused storytelling around the middle of the first season. By the second season, Kripke's mandate was "to put characters first and monsters second."

I asked why the series often revisited the distrust between its two heroes: "I just think that conflict is the basis of good drama," adding that the seasons where Sam and Dean's relationship was less dysfunctional were less interesting. He says that at their core, each Winchester brother was hand-picked by each side of the cosmic divide--Sam by Hell, Dean by Heaven--which gave the series much of its mileage in its first five seasons. Subsequent years have involved the two of them passing through the revolving door of death, coming back changed somehow, and having to overcome their initial distrust of one another.

On storytelling, Kripke allows that a writer should allow the characters to surprise them, even as a series like "Supernatural" has a deep mythology, which was so thoroughly plotted out in its first four seasons around devils that Kripke initially wouldn't entertain the idea of having angels as part of the story. But around season four, he felt like there was a missing piece, ultimately adding the character of Castiel to represent another side of the conflict for the human soul.

He shared the origins of an episode that almost got away, the reality TV inspired "Ghost Facers" where Sam and Dean come into contact with a camera crew trying to find real-live ghosts. He said that writer/"The Tick" creator Ben Edlund came into the writer's room with a guitar and began playing the theme song for the this imaginary reality show, and within days, the writer's strike happened. Kripke says he was in a panic that not only would it be possible that the series might not get to "Ghost Facers," but that "Supernatural" would fail to return altogether.

"The Essential Supernatural: On The Road With Sam and Dean" is available now from Insight Editions.