The volume called Higher Mathematics, the first edition of which was published in1896, contained eleven chapters by eleven authors, each chapter being independentof the others, but all supposing the reader to have at least a mathematical trainingequivalent to that given in classical and engineering colleges. The publicationof that volume is now discontinued and the chapters are issued in separateform. In these reissues it will generally be found that the monographs areenlarged by additional articles or appendices which either amplify the formerpresentation or record recent advances. This plan of publication has beenarranged in order to meet the demand of teachers and the convenience of classes, but it is also thought that it may prove advantageous to readers in special linesof mathematical literature.It is the intention of the publishers and editors to add other monographs tothe series from time to time, if the call for the same seems to warrant it. Amongthe topics which are under consideration are those of elliptic functions, the theoryof numbers, the group theory, the calculus of variations, and non-Euclideangeometry; possibly also monographs on branches of astronomy, mechanics, andmathematical physics may be included. It is the hope of the editors that thisform of publication may tend to promote mathematical study and research overa wider field than that which the former volume has occupied