Instrumental techniques of analysis have now moved from the confines of the chemistry laboratory to form an indispensable part of the analytical armoury of many workers involved in the biological sciences. It is now quite out of the question to considcr a laboratory dealing with the analysis of biological materials that is not equipped with an extensive range of instrumentation. Recent years have also seen a dramatic improvement in the ease with which such instruments can be used, and the quality and quantity of the analytical data that they can produce. This is due in no sm all part to the ubiquitous use of microprocessors and computers for instrumental control. However, under these circumstances there is areal danger of the analyst adopting a 'black box' mentality and not treating the analytical data produced in accordance with the limitations that may be inherent in the method used. Such a problem can only be overcome if the operator is fully aware of both the theoretical and instrumental constraints relevant to the technique in question. As the complexity and sheer volume of material in undergraduate courses increases, there is a tendency to reduce the amount of fundamental material that is taught prior to embarking on the more applied aspects. This is nowhere more apparent than in the teaching of instrumental techniques of analysis.