Harry Potter Trading Card Game these expansions include the addition of the "Quidditch" lesson type and "Match" cards introduced in the "Quidditch Cup" expansion, location cards introduced in the "Diagon Alley" expansion, and a larger pool of adventure cards in the "Adventures at Hogwarts" expansion. The fourth and final expansion released was "Chamber of Secrets", which has 140 cards plus 55 Foil or Hologram Portrait Premium rares (October 2002). This last expansion features cards based on the "Chamber of Secrets" book, where all previous cards were based on the "Sorcerer's Stone" book. From its conception in 2001 through 2003, the "Harry Potter Trading Card Game"
The Magical Worlds of Harry Potter it was "cool that their hero, Harry, was encountering some of the creatures of mythology." Colbert felt that knowing the origins of Rowling's character and creatures increased "the books' magic tenfold" and made the "Harry Potter" universe seem more lifelike. Feeling that he wanted to share this with others, Colbert spent a year researching the references in the novels and collected his discoveries for a guidebook to the magical world of Harry Potter. Colbert wrote "The Magical Worlds of Harry Potter" while teaching a seminar on self-publishing to graduate students at the University of North Carolina. He had it self-published