This report from the United Nations Economic and Social Council presents guidelines for a thematic discussion on the challenge posed by emerging forms of crime that have a significant impact on the environment and effective ways for dealing with the problem. The format of the guide is a series of questions related to a set of themes and sub-themes. The two main themes as they relate to environmental crimes are 1) challenges posed by emerging forms of crime that have a significant impact on the environment, and 2) possible responses, programs, and initiatives to deal effectively with forms of crime that have a significant impact on the environment. The sub-themes covered in the guide that deal with the challenges posed by environmental crime include emerging trends and challenges, including those linked to data collection and its analysis, criminalization, and criminal justice; and challenges linked to related offenses. The two sub-themes that deal with the possible responses to this problem are possible ways to increase effectiveness of preventive and responsive measures of criminal justice systems, including using existing international treaties to combat crime; and international collaboration and partnerships, including the role of the United Nations Office on Drugs and Crime (UNODC) in counteracting unlawful conduct that may have a negative impact on the environment. The final section of the guide includes a list of activities of the UNODC in the field of environmental crime.