This paper re-examines the rationale for pre-school intervention programmes and the results from a variety of programmes are reviewed. The distinction is drawn between programmes for the socially disadvantaged and for the handicapped. The importance of parental involvement in such programmes is discussed, both with regard to advantages for the child and for the family. The wide variety of pre-school programmes that are possible are examined with consideration given to the population served, the geographical area, the theoretical basis and delivery systems. Considerable attention is paid to the difficulty of evaluating any pre-school intervention programme. With these points in mind, home visiting, a popular form of pre-school intervention with practitioners, is examined and advantages and disadvantages of this form of intervention are enumerated. The paper ends with a cautionary note, and attention paid to authors who feel that early intervention can have dangers. The conclusion drawn is that better documentation of the work going on in the field is the only way to overcome gaps in our knowledge and to individualize services to parents and to children.