Question: is the tv show supernatural based on a book

Answer: No, Before bringing Supernatural to television, creator Eric Kripke had been developing the series for nearly ten years, having been fascinated with urban legends since he was a child. He had originally envisioned Supernatural as a movie. He later developed it as a TV series and spent a few years pitching it before it was picked up by The WB. The concept went through several phases before becoming the eventual product, shifting from the original idea of an anthology series to one of tabloid reporters driving around the country in a van ``fighting the demons in search of the truth''. Kripke wanted it to be a road trip series, feeling that it was the ``best vehicle to tell these stories because it's pure, stripped down and uniquely American... These stories exist in these small towns all across the country, and it just makes so much sense to drive in and out of these stories.''