The publication by the ILO of new estimates on forced labour in 2012 created a sense of urgency for addressing implementation gaps relating to the ILO's Forced Labour Conventions, leading to the adoption of supplementary standards by the 103rd International Labour Conference in June 2014. The power of normative pressure against those who still use or condone the use of forced labour is essential, and national legislation needs to be strengthened to combat forced labour and penalties against those who profit from it need to be strictly enforced. However, a better understanding of the socio-economic root causes and a new assessment of the profits of forced labour are equally important to bringing about long-term change. This report highlights how forced labour - which in the private economy generates US$150 billion in illegal profits per year, about three times more than previously estimated - thrives in the incubator of poverty and vulnerability, low levels of education and literacy, migration and other factors. The evidence presented illustrates the need for stronger measures of prevention and protection, as well as for enhanced law enforcement, as the basic responses to forced labour. At the same time, the report offers new knowledge of the determinants of forced labour, including a range of figures that break down profits by area of forced labour and by region. This can help us develop policies and programmes not only to stop forced labour where it exists, but to prevent it before it occurs.