We have written this book in order to assess the achievements of microenterprise finance institutions from a comparative point of view. Very much of what is written about such institutions, both for good and for evil, focuses on prominent individual institutions and contains no numbers other than those demanded by accountants, so that the wider influences of such schemes on borrower income, employment and technology, on the overall financial market and, above all, on poverty are often assumed rather than measured. In the process, the success of institutions such as the Grameen Bank and BancoSol in ‘walking the tightrope’ between ineffective targeting and financial failure comes to be seen as something straightforward and inevitable, their many experiments and changes of direction are obscured and the failure of many institutions who have tried to emulate them have been cast into outer darkness. Walking a tightrope is what micro-finance remains, and it is right to emphasise the risks run by those who undertake it and to salute the achievements of the institutions, including several described in Volume 2, who have done so successfully. They have achieved something thought by most people, until about ten years ago, to be impossible.