The aim of this study is to identify risk factors that can lead to boys/young men carrying out criminal deeds and getting involved in gangs. This study is based on two biographic books that describe the lives of two men that are former criminals, and the circumstances that led to them carrying out criminal deeds and eventually joining criminal gangs. A content analysis has been used when reading the two biographic books to gain understanding of and identifying the risk factors that led these two men to carrying out criminal deeds and getting involved in gangs, furthermore this empirical data has been analysed with previous research, the anomie theory, and the strain theory. In the case of these two men there was not a single risk factor or circumstance that led them to criminal behaviour, but rather a multitude of different risk factors. The risk factors that were identified in the two biographic books are individual traits such as a tendency to aggression and impulsive behaviour. Other risk factors that can lead to criminal behaviour are school failure, using drugs and having friends that engage in deviant/criminal behaviour. Living in a residential area with high levels of crime and drug use is also a risk factor. The two biographic books have also shown that especially lacking family and socioeconomic circumstances such as the occurrence of violence and neglect in the home, lack of love, care and support by the parents, parents using up the money on alcohol and gambling and the resulting poverty, can constitute risk factors for delinquency. Risk factors such as the person using different strategies to justify deviant behaviour, having a history of crime, having a need of belonging and higher status/respect can lead to gang involvement. These findings have shown that it is important for institutions such as schools and social care units to put emphasis on working against the risk factors and supporting adolescents and families, in order to prevent boys/young men from carrying out criminal deeds and getting involved in gangs.