The obscure problems of psychology had a great attraction for him, and he spent much time in investigating them, being one of the founders, and remaining all through his later life a leading and guiding member, of the Society for Psychical Research, which has for the last twenty years cultivated this field with an industry and ability which have deserved larger harvests than have yet been reaped. Two remarkable men, both devoted friends of his, worked with him, Edmund Gurney and Frederic Myers the poet, the latter of whom survived him a few months only. It was characteristic of Sidgwick that he never committed himself to any of the bold and possibly over-sanguine anticipations formed by some of the other members of the Society, while yet he never was deterred by failure, or by the discovery of deceptions, sometimes elaborate and long sustained, from pursuing inquiries which seemed to him to have an ultimate promise of valuable results. The phenomena, he would say, may be true or false; anyhow they deserve investigation. The mere fact that so many persons believe them to be genuine is a problem fit to be investigated. If they are false, it will be a service to have proved them so. If they contain some truth, it is truth of a kind so absolutely new as to be worth much effort and long effort to reach it. In any case, science ought to take the subject out of the hands of charlatans. The main business of his life, however, was teaching and writing. Three books stand out as those by which he will be best remembered--his _Methods of Ethics_, his _Principles of Political Economy_, and his _Elements of Politics_. All three have won the admiration of those who are experts in the subjects to which they respectively relate, and they continue to be widely read in universities both in Britain and in America. All three bear alike the peculiar impress of his mind.