Dr, Kreizler is an alienist, or psychiatrist, who specializes in child and criminal psychology. In the book he is the main driving point of the investigation and is the reason most of the information was found or even considered in the story since he believed to build the killer up from his childhood. One of Kreizler's arms is injuried which is mentioned often in the story.

Dr.Kreizler is centralized heavily around the theory of 'context', or the theory that an individual's personality and behavior is determined by their childhood experiences. He got his education in phychology in the mid 1870s at Harvard where he met Roosevelt and had a course under the minor character William James. Prior to Harvard he worked at an asylum in a place on Blackwells Island. In the book when is he not focused on the investiagtion most of his time is spent at Kreizler's Institute for children with emotional and phychological disorders he also frequents multiple jails where crimals are to evaluate their mental states. His home life and his job intermix a lot since he lives with one of his former patients named Mary, and has another that works for him known as Cyrus.

Kreizler was born in Europe, and emigrated to the United States as a child when his weathy German father, and Hungarian mother fled from persecution to begin a somewhat new life in New York. Despite growing up in America in his home he was forced to speak German and therefore he kept his German accent which is pernounced throughout the story with a hint of a Hungarian one. Kreizer childhood isn't something he talks about often. John Moore descries how his parents used to throw grand parties which European luminaries would be invited. His parents were seen as quite great, but as it is revealed in the story his father is an abusive alcoholic. And Kreizler is said to have been being beaten the most severe injury from his father is his disfigured left arm.

Kreizler is one of the most important characters in the story for not only being the driving force and fund of the investigation but for being the one to even set it up. He does have details that effect his character greatlyy through the story. It very faint and isn't something prominet in the story since Kreizler had always paid very close attention to other characters ideas. Though he seems to have a very set opinion on who can be abusive and who couldn't in the story he gets into a loud fight with Sara since he doesn't believe that a woman could be abusive most likely because he was hit by his own father. This caused a brief rift in the investigation.

Bad qualities

Despite being one of the most developed characters in the story besides the killer he doesn't exactly have anymore bad qualities that are visible in this story. Kreizler is somewhat of a myster in himself because while we have a general idea of his past we never fully get more information on it. And the information we do have didn't even come from Kreizler himself, but from files that were found under his name detailing injuries that gave insight to his past.

Overall Kreizler is a very smart and well developed character that has a lot of depth that isn't touched upon in this story. He is one of smartest and more helpful in the story though his methods are seen as odd in his timeline.