This text is to addresses the requirements of the analyst working in a materials laboratory from a practical angle providing reference where necessary to more detailed work. It also shows the link between XRD and other analytical techniques with integral diffraction facilities. Some applications are briefly discussed to show what can be achieved; others to show what to look for and what to check. The provision of computing facilities, while having many benefits, can also lead to a false reliance in the output that they generate. The importance of the errors that can occur, how to handle them and the need to provide some measure of uncertainty to the customer are considered. It does not purport to be universal in its coverage.