Book excerpt: This book aims to enable non-experts in Genetics to understand the contribution of this science to resolve civil or criminal litigations, analysing evidence of human and non-human origins. The main difficulties in the comprehension and misuse of the results of Forensic Genetics reside in the lack of effective communication between geneticists and the users of the produced information (as lawyers and judges) and do not arise primarily from the lack of knowledge of genetics. Therefore, instead of a classical handbook we use a question-and-answer approach, which meets this interfacial essence. Questions that can be addressed by genetic expertise are typified and for each of them we provide the possible expert report, presenting the essential biological and statistical genetics background in the form of boxes/appendices, along with exemplary cases. Legal, ethical, and theoretical limitations of Forensic Genetics are discussed, formulating questions that cannot, or should not, be addressed by this applied science.