The final book in the series was "Hannibal Rising". It shows Lecter as a child. It tries to explain why he is a murderous cannibal by describing the death of his family during World War II. The critics did not like "Hannibal Rising" as much as they liked the first three books. This was mainly because people thought that the story was unrealistic. They also felt it was not true to the characters. Thomas Harris has said in many interviews that he only wrote the book because he was afraid that someone else would write a book about Lecter as a child. This book was also the basis for a film of the same name, with Gaspard Ulliel as young Hannibal.