AMONG the eighteen papers in the Rendiconti del Seminario Mathematico e Fisico di Milano (7, 1933), the longest, and, to the general reader, most interest ing, is an account of the scientific work of G. Peano of Turin (1858-1932). His publications, numbering more than two hundred, ranged over pure and applied mathematics, logic, philosophy, grammar, com parative philology, international languages, and even politics. Some early papers dealt with the algebra of invariants. He then turned to calculus and differential equations. His ‘space-filling curve’ has been described as one of the most remarkable results in the theory of aggregates. The investigations of the foundations of geometry and arithmetic are of great importance, but his crowning achievement is his system of mathematical logic, with its elaborate symbolism (the ‘Peanese’ ridiculed by Poincare), which has been used in England by Russell and Whitehead. Peano applied his logical methods to grammar, and this led to other linguistic studies, including the invention of the international language Interlingua. As a contrast to his abstract work may be mentioned his methods for the approximate solution of problems in practical mathematics. He stands out in the history of science as one of the few modern thinkers who have combined profound originality with a wide range of activities.