John Marquis is a former police prosecutor and for seven years the Officer in Charge of the Research and Training Section of the Prosecutions Division of the Victoria Police Force. He was extensively involved in prosecuting, instructing, researching and providing legal advice in all areas of the criminal law. As Officer in Charge of the Research and Training Section, he was responsible for over sighting and contributing to the Victoria Police Prosecutors Manual. For six years he was the Victoria Police representative on the Police and Lawyers Liaison Committee. He is a senior instructor at the Leo Cussen Institute - Practical Training Course in the areas of criminal law, evidence and advocacy. He is also an instructor at the Bar Readers Course. His academic qualifications are B Juris (Mon) LLB (Hons) (Mon) and LLM (Criminal Justice and Litigation) (Mon). He is co-author of Butterworths, Motor and Traffic Law Victoria.