It is generally agreed that all the sciences, both social and natural, are related, particularly through the exchange of experiences, ideas, materials, methods, perspectives and theories. This 'give-andtake' phenomenon is, to a large extent, factual and, thus, establishes a power-equilibrium or a balance-ofpower relationship among the various disciplines. In our view, to accept this notion wholly without subjecting it to a critical scrutiny would, however, not be fair enough to history, which, from all indications, occupies a special and a privileged position among the sciences. The reason is that apart from these usual exchanges, each particular discipline has its particular history which it studies, thereby producing such disciplines as the history of accounting, of anthropology, of astronomy, of biology, of chemistry, of economics, of geology, of legal studies, of mathematics, of medicine, of philosophy, of sociology, of zoology, etc. This fact naturally demands a compulsory study and reconstruction of the history of each discipline by the scientists who practise it in order to appreciate the context in which it evolved and developed, so as to understand its present circumstances and have a perspective of its future. We express the specific image - the mental picture - we have of this natural and unending expansion of the influence and authority of history into the territories of other disciplines in terms of what we call 'historical imperialism in science'. Using both secondary and primary data, and arbitrarily selecting accounting, economics and philosophy from the social sciences; and astronomy, mathematics and medicine from the natural sciences for illustration, we seek to show that each particular discipline has its particular history, and so most scientists study and practise history in their respective disciplines, use historical data, and employ historical approaches, in order to understand the present position of their disciplines and to have a view of the future of their subjects. Based on the successful formulation and substantiation of the reality, authenticity and superiority of the theory of 'historical imperialism in science', we maintain that the study of history is very crucial for the survival of all disciplines, and so the significance of history at any particular point in time could be measured partly in terms of its contributions to the intellectual growth and development of all disciplines. We conclude that this realisation should be used as a justification for the serious study of history both as a separate subject in the school curriculum and as an integral part of each discipline in order to sustain the development of the disciplines, so that society could continue to benefit from their invaluable individual and collective contributions.