There is greater gender and racial/ethnic diversity in top corporate leadership in the new millennium than existed even three decades earlier. Nevertheless, visible leadership remains primarily white and male. The goal of this literature review is to examine critically the commonly debated explanations of why women's progress to upper levels of corporate leadership has been slow. The literature review identifies external barriers such as the workplace not being designed with women's needs in mind, the burdens of tokenism, and covert discrimination, especially against women of color. The paper concludes with the observation that, more than anything else, the perception of leadership as a masculine activity and the belief that women lack the necessary qualifications to function effectively in executive positions explain why so few women have reached the top of the corporate hierarchy. The good news is that if decision makers are familiar with a woman and her record of accomplishment, she is more likely to be promoted. In other words, knowledge of a woman's work can trump the negative impact of stereotypes.