Not All Dogs Go to Heaven "American Dad!" character, Avery Bullock in "Lois Kills Stewie" (season 6, episode 5), and his "Star Trek: The Next Generation" character Captain Jean-Luc Picard in "Peter's Got Woods" (season 4, episode 11); Jonathan Frakes, Michael Dorn and Marina Sirtis also appeared in "Peter's Got Woods" as their respective "Star Trek: The Next Generation" characters William Riker, Worf, and Counsellor Deanna Troi. "Not All Dogs Go to Heaven" features the entire original cast of "Star Trek: The Next Generation": Stewart as Captain Picard; Frakes as Riker; Gates McFadden as Doctor Beverly Crusher; Brent Spiner as Lieutenant Commander Data; Dorn as Worf;
In Theory (Star Trek: The Next Generation) on VHS cassette, appearing on September 5, 1991, in the United States and Canada. The episode was later released on LaserDisc on September 24, 1996, and also included on the "Star Trek: The Next Generation" season four DVD box set, released in the United States on September 3, 2002. The first Blu Ray release was in the United Kingdom on July 29, 2013, followed by the United States on July 30. In Theory (Star Trek: The Next Generation) "In Theory" is the 25th episode of the of the American science fiction television series "", originally aired on June 3, 1991,