The first edition of this work, which is perhaps the best known book on hygiene, was published in 1889. Its contents and general character are too well known to need description. While in some fields the book has been brought down to date, in others it is not in accord with American ideas. An immunologist might regret the space spent on Ehrlich's theories almost to the exclusion of more recent conceptions of infection and immunity. It is often a pleasure to see old book friends revive, and this edition is no exception.