AbstractThree phases of development of the subject of evaluation are identified. Up to 1979 it was still in its infancy, with the main impetus coming from the USA (the World Bank and US AID), and from one or two large UN organizations, although the OECD also did some useful work in bringing evaluators together.The second phase (1979‐1984) saw rapid ‘take‐off’, with greatly increased resources going into evaluation work, and a veritable ‘explosion’ of interest worldwide. All the main donors had by now set up evaluation units and were amassing enough material to begin to ‘synthesize’ the findings. The OECD provided a focus and a forum through its Expert Group on Aid Evaluation.The third phase, from 1984 onwards, finds the subject having ‘come of age’, its maturity being marked by the publication of major works such as Cassen'sDoes Aid Work?.The emphasis now is switching from ex‐post evaluation towards improving project design through such techniques as