An essay on the psychology of invention in the mathematical field. Hadamard, Jacques, 1865-1963. Mathematics Philosophy. Psychology. Inventions. QA9 .H25 1954 510.15 HAE "An unaltered and unabridged reprint of the first edition." Bibliographical footnotes. [New York] Dover Publications 1945. 1945. 1954 Text xii, 145 p. ; eng