The financial crisis that engulfed the world in 2007 and 2008 has led to a wave of re-regulation and discussion of further regulation that has culminated in the proposals from the Basel Committee as well as those in the Vickers Committee report on Banking Regulation and Financial Crises. This issue of the Review contains a number of papers on Banking Regulation, covering many aspects of the debate, and we can put that debate in perspective through these papers and also by discussing our work on the relationship between bank size and risk taking, which is reported in Barrell et al. (2011). We addressed the causes of the crisis in the October 2008 Review, and began to look at the costs and benefits of bank regulation in Barrell et al. (2009). In that paper we argued that we needed to know the causes of crises and whether the regulators could do anything to affect them before we discussed new regulations. It is now generally agreed that increasing core capital reduces the probability of a crisis occurring, and most changes in regulation that are being discussed see this as the core of their toolkit. The work by the Institute macro team in Barrell et al. (2009) and in Barrell, Davis, Karim and Liadze (2010) was the first to demonstrate that there was a statistically important role for capital in defending against the probability of a crisis occurring, and our findings were widely used in the policy community in the debate over reform.