Knife crime is a persistent problem in the United Kingdom. Between 2014 and 2020, the number of violent incidents involving knives or sharp objects rose year-on-year, with 2019/20 witnessing the largest number of police-recorded knife offences in the past decade (Allen and Harding, 2021). The societal, economic and health implications of knife crime are both significant and highly concentrated. The burden of knife crime falls disproportionately on young males in deprived and metropolitan areas (Massey, Sherman and Coupe, 2019); (Sutherland and others, 2020). The guide contains six main sections.  It begins by defining knife crime and clarifying the different types of knife crime and what the guide does and does not cover.  It then provides a short summary of the background, purpose and effectiveness of police problem solving.  The remaining four sections are organised around SARA, the most common framework for doing problem solving.  Scanning is about clearly defining your local knife crime problem. This section describes the sources of data and intelligence that can be used to better understand the trends and patterns in your local knife crime problem.  Analysis is about working out why your knife crime problem persists. This section outlines some critical questions to ask of available data, and describes how to use data to better tailor and target interventions.  Response is about designing and delivering interventions aimed at reducing knife crime. This section reviews the research evidence associated with common knife crime interventions. It also presents a framework to help work out whether particular interventions might be relevant to tackling your own local knife crime problem.  Assessment is about learning lessons and driving improvement. This section deals with how you measure the effectiveness of your knife crime interventions. It sets out principles for good evaluation and what you can do to know if your local knife crime problem has changed as a result of your chosen activities.