WE publish in this issue an article by A. Erdelyi add John Todd, entitled “Advanced Instruction on Practical Mathematics”, which follows an earlier article by D. H. Sadler and John Todd (Nature of Ma, p. 571), “Mathematics in Government Servge and Industry: some Deductions from the War-time Experience of the Admiralty Computing Service”. They claim that it has now been fully demonstrated that there is a need, in Government departments such as the Admiralty, the Ministry of Supply and Aircraft Production, and in industrial research associations or research departments of engineering or other firms, for a new type of mathematician, whom Dr. N". W. MacLachlan has called a ‘mathematical technologist’. Such a man will have a good knowledge of academic mathematics, but in addition will know how to apply this knowledge to obtain a complete approximate solution, with full numerical calculations, of an engineering or. other problem. Much of modern academic mathematics is of a qualitative nature. We prove that a solution of a problem exists, under certain conditions, and that this solution has certain properties, such as breaking down at specified exceptional points. The mathematical technologist will not be ignorant of this, but will supplement it with detailed quantitative knowledge, giving all the information required to any desired degree of approximation. So far the universities of Great Britain have done little or nothing to produce such men. What should be done about it?