There were bookshelves in all of the rooms, and I noted that the owner, however many the guests had been, or long the evening, never went up to bed without a book in his hand. I came later to know how fixed this night-reading habit had become, for in the Belgian relief years when we had frequently to cross the perilous North Sea together on our way from Thames-mouth to Holland or back in one of the little Dutch boats which used to run across twice a week until most of the boats had been blown up by floating mines, Hoover used always to fix an electric pocket lamp or a stub of a candle to the edge of his bunk and read for a while after turning in. He has had little time for reading in daytime, but yet he has read enormously. It is this night-reading that explains it. The shelves in "The Red House" contained many books about geology and mining and metallurgy. But they contained many others as well. Especially were they burdened with books on economics and political science. And they bore lighter loads of stories. Sherlock Holmes was there _in extenso_. The books on civics and economics and theories of finance were well thumbed and some of them margined with roughly penciled notes. I should say they had been studied. A frequent evening visitor, who came by preference when there had been no guests at dinner, was a well-known brilliant student of finance and economics, formerly editor of the best-known English financial weekly and now editor of a very liberal, not to say radical, weekly of his own. He and Hoover held long disquisition together, each having clear-cut ideas of his own and glad to try them out on the keen intelligence of the other. As a mere biologist, whose little knowledge was more of the domestic economy of the four and six-footed inhabitants of earth than of the social science and politics of the bipedal lords of creation, my role was chiefly that of fascinated listener. Although he likes books and even likes writing, Hoover makes no claims to authorship himself. Nevertheless he has found time to put something of his knowledge, based on firsthand experience of the fundamentals and details of mining geology, and mining methods and organization, into a book which, under the title of _Principles of Mining_, has been a well-known text for students of mining engineering since its appearance in 1909. The book is a condensation of a course of lectures given by the author partly in Stanford and partly in Columbia University. Although it contains an unusual amount of original matter and old knowledge originally treated for the kind of book it professes to be, namely a compact manual of approved mining practice, the author's preface is a model of modest appraisement of his work. One of its paragraphs simply demands quotation: