This article deal with applications of neutron diffraction in materials science. Most of the examples presented here involve the use of powder diffraction. In most of these, the Rietveld method has been used for data analysis. There is an emphasis on the quantitative phase Rietveld method. This being an application which was largely pioneered at Lucas Heights. Examples involving single crystal diffraction and neutron polarization analysis are also included. Most of the examples are drawn from studies carried out at Lucas Heights where there is a strong program on the application neutron diffraction to the study of ceramics, and this is reflected in the choice of examples to be considered in this article.