We make sense of our world and go about our daily lives by engaging in concept building. We acquire and develop concepts so that we can gain meaning about persons and events and in turn communicate these meaning to others. Some concepts are clearly of more importance than others. The key concepts
provide us with the power to explore a variety of situations and events and to make signiﬁcant connections. Other concepts may be meaningful in more limited situations but play a part in connecting unrelated facts. Every ﬁeld of study contains a number of key concepts and lesser concepts
which relate to substantive and methodological issues unique to that discipline/ ﬁeld of study. Not unexpectedly, scholars diﬀer over their respective lists of key concepts, but there is, nevertheless, considerable agreement (see, for example, Hayes, 2006). With regard to the curriculum ﬁeld there is a moderate degree of agreement over key concepts.