Research on aid costs suggests that institutional costs matter more to recipients than administrative costs, greater ownership and trust require greater capacity and that potential benefits from reform of aid management should be greatest where aid dependence is high and government capacity low. The articles in this Public Administration and Development Special Issue illustrate aid management problems and ways forward, with country studies of Bolivia, Bangladesh, Cambodia, Mozambique, Samoa and Vietnam. The overall conclusion is that putting the new orthodoxy in aid management (alignment, harmonisation, budget support and government-led collaboration) into action widely is hindered by lack of a clear strategy for raising capacity in recipient countries.As the report of the Commission for Africa (2005) notes, the findings of recent impact investigations are giving aid a better press: World Bank's aid financed projects typically have high returns (World Bank, 2004), aid improves education and health (Oxfam, 2004), aid supports growth and investment (McGillivray, 2004), reduces capital flight (Collier et al., 2004), helps to improve institutions and governance (Chauvet and Collier, 2005), helps countries to withstand shocks to export prices (Chauvet and Guillaumont, 2004) and rebuilds post-conflict societies.But at the same time aid management is increasingly criticised (OECD-DAC, 2003; Paris Declaration on Aid Effectiveness, 2005) for the costs that it imposes on recipients, particularly in smaller, aid dependent countries: for making government accountable to donors rather than to their own electorate; for placing unreasonably restrictive conditions on their aid, being too short-term in their aid commitments and too unpredictable in their disbursements; for the burden that dealing with numerous uncoordinated donors and donor systems is believed to place on recipient administrations; for alleged fragmenting and undermining of government planning and budget processes when donors set up their own parallel structures in country; and for attracting key personnel out of government with higher pay. Far from being essential for effective aid, it is argued, such costs reduce the effectiveness of aid.The possibility that reform in donor practices can reduce aid costs to recipients opens the prospect that higher levels of aid (as pledged at Monterrey) might be employed without reducing its effectiveness. There is a new orthodoxy in aid management designed to achieve this, consisting of four main innovations. First, under the banner of 'alignment' donors should adopt the objectives and targets of the recipient government's poverty reduction strategy and budget, and use the recipient government's own planning, management, accounting and reporting systems wherever possible. Second, under the banner of 'harmonisation' donors are urged to simplify and unify their procedures and conditions, share analytic work and rely on each other-delegated cooperation-rather than multiplying the donor presence in countries. Third, budget suppo...