Referee's report by Kathleen Yardley Lonsdale, on a paper 'The refinement of atomic parameters by the technique known in X-ray crystallography as ‘the method of steepest descents’' by A D Booth Sectional Committee: Mathematics Recommended for publication in the 'Proceedings of the Royal Society of London'. All the paper is relevant, as this is the first mathematical formulation of the method. Notes some minor criticisms. Suggests an alternative title, to make the contents clearer. [Published in the 'Proceedings of the Royal Society of London'] No received date. [1948]