Grey's Anatomy is an American medical drama television series that premiered on American Broadcasting Company (ABC) as a mid-season replacement on March 27, 2005, and is currently in its 12th season. The series focuses on the fictional lives of surgical interns and residents as they gradually evolve into seasoned doctors, while trying to maintain personal lives and relationships. The title is a play on the name Gray's Anatomy, an English-language human anatomy textbook originally written by Henry Gray. The show's premise originated with Shonda Rhimes, who serves as an executive producer, along with Betsy Beers, Mark Gordon, Krista Vernoff, Rob Corn, Mark Wilding, and Allan Heinberg. The series was created to be racially diverse, utilizing a color-blind casting technique. While the show is set in Seattle, it is primarily filmed in Los Angeles, California.