This Working Paper is a literature review, undertaken with the aim of better understanding how to improve working and employment conditions of women and men in micro and small enterprises (MSEs) and the informal economy on a large scale, in a more comprehensive manner, and taking into account the links of this effort with other key development problems, particularly poverty and gender equality. It supports TRAVAIL's learning and research agenda, which involves defining the vision for improving working and employment conditions and how changes might be achieved, encompassing the following three key aspects: scale, impact and sustainability. The literature review is a first step, aimed at identifying what has been tried and what has worked in experiences around the world related to conditions in the informal economy and MSEs. A number of important lessons can be extracted from the diverse experiences that are reported on here, that can be applied to the design and implementation of future programmes.