This text aims to give lawyers a complete account of the issues involved in taking DNA evidence into court. It guides the reader through the process of generating results from all types of trace samples. It raises questions such as: once DNA results have been produced how are they interpreted?; why is a database sometimes required, but not always?; how close to an ethnic group does a database need to be before it can be regarded as reliable? Such questions as these allow the reader to work through DNA evidence in all types of case: it is not just crimes against the person where it can be used, but anywhere where contact has taken place and cells left behind. The book should help lawyers to ask the most important and probative questions when faced with such evidence in court.