The purpose of this investigation was to discover the origins of the vertical curriculum structure that has made a considerable impact on state secondary schools in the last decade and to establish how the idea spread throughout the system and why schools made this major change away from the horizontal curriculum. Three research methods were used in this study. Firstly, Education Department secondary school handbooks were studied to identify the vertically structured schools in 1975 and 1982. Secondly, a telephone survey was undertaken in order to find more information about each of the 44 vertical models discovered in the 1983 handbook. Finally, the key carriers of the concept were interviewed to gain in depth information on the innovation. The outcome from the data collected should assist in the understanding of how a major curriculum change can disseminate throughout the schools in an education system.