The Manuscript Section of the "G. Peano" Library of the Department of Mathematics of the University of Turin has in its keeping an important collection of manuscripts by Corrado Segre 1 (Saluzzo 1863-Turin 1924), the founder of the Italian school of algebraic geometry, in whose ranks are numbered such distinguished mathematicians as Guido Castelnuovo, Francesco Severi, Federigo Enriques, and Gino Fano. The most important part of this collection is in the form of forty books of lecture notes, together with Segre's degree dissertation, memoirs, articles, and notes and a card index, containing a valuable collection of bibliographical indications divided according to topic [Giacardi and Varetto 1996].
In particular, the notebooks in which, every summer, Segre made a careful record of his lectures for the courses he was to teach in the following autumn are not only extraordinary evidence of his gifts as a teacher, but also important historical documentation on his research activity, of which, as Alessandro Terracini remarks, they are sometimes "a preliminary stage," sometimes "a reflection" [Terracini 1953, 261].
His students bear copious witness to this. Castelnuovo, who spent four years of fertile academic activity in Turin, writes "He devoted himself to teaching with the fervour of an apostle" [Castelnuovo 1924, 460], and Fano, who was lucky enough to follow his university courses, stresses his great gifts as a teacher in the following words: "He considered it a true mission to direct his students towards the upper levels of mathematics, and especially of geometry, encouraging them whenever possible to produce original work ... He lavished infinite care and treasures of knowledge on his 36 courses of advanced geometry, the subjects of which he himself expounded in writing, in his clear, distinct hand, in little books which his old and recent students were very familiar with, always very precisely worded and with numerous bibliographical quotations, with complements which gradually occurred to him, often with original ideas and opinions, with indications of topics for further research, from which he drew the subjects he suggested for degree dissertations" [Fano 1924[Fano -1925, 225-226], 225-226]. "He was one of the most careful in the preparation of his Lectures, that I have ever known," writes Severi. "In fact they were written in advance word for word and in definitive form in little booklets, which he took with him to his lectures, so that he could give