One interesting theory on the cause of manic depression or bipolar disorder is that there is a super-fast biological clock located in the hypothalamus, in the center of the brain, which is actually a tiny cluster of nerves called the supra chiasmatic nucleus or SCN.
Since the release of the first novel, Harry Potter and the Philosopher's Stone, on 26 June 1997, the books have found immense popularity, critical acclaim and commercial success worldwide.
An illustrated version of Harry Potter and the Philosopher's Stone was released on October 6, 2015, with illustrations by Jim Kay. The book carries over 100 illustrations and will be followed by illustrated versions of all seven books from the series by the same artist.