I suggest a historico-philosophical overview, assessment and explanation of the variety of materialism that was developed from the late 1950s onwards in Australia, primarily by U.T. Place, J.J.C. Smart, and D.M. Armstrong. These authors spoke less of "materialism" and more of an "identity theory," that is, a theory concerning the nature of the relation between brain and mind – not matter and mind in general, notice – which they wished to show was an "identity." In order to explain, survey and assess this intellectual episode I examine some of its roots in the Vienna Circle (its closest "correspondent" in the United States was Herbert Feigl, who had been a member of the Vienna logical positivists), the way in which it reacted to behaviorism, and its 'success' in Anglo-Saxon philosophy of mind in the years since then. Having done so, I evaluate the pertinence and novelty of this kind of materialism in relation to philosophical materialism more broadly defined, and this will lead me to formulate some criticisms of the Identity Theory.