In this paper an attempt is made to review in rather broad perspective the origins and history of quantitative methods in diffraction analysis, at the same time leaving an in-depth examination of the present state of the art to other better qualified contributors to this conference. Space limitations preclude mention of many significant contributions, for which I am very sorry. It will be possible to review only a number of pivotal historical events, while also taking note of certain other researches that seem representative of historical and present-day trends.
The birth of quantitatively meaningful analysis in the mid-1930s depended upon a realisation of, and allowance for, the alteration of the diffracted intensities resulting from absorption of x-rays by the specimen. Furthermore, advances in the art achieved during the past forty years have been closely related to improvements in the treatment of the absorption factor.