Authentic health literature existed abundantly before the preparation of these volumes, but it was scattered, expensive, and in most cases not arranged for the widest use. Not within our knowledge has the body of facts, most helpful to the layman on Sanitation and Hygiene, First Aid, and Domestic Healing, been brought together as completely, as clearly, as concisely, with a critical editing board so qualified, and with special contributions so authoritative as this work exhibits. "Utmost caution" has been a watchword with the editors from the start. Those to whom the doctor _cannot come every day_ have been repeatedly warned of the follies of self-treatment, and reminded that to-day it is the patient that is treated--not the disease. Those to whom the doctor _cannot come in time_ are likewise warned that the "First-aid Rules" of this Library are for temporary treatment only, in all situations where it is possible to get a physician. And the utmost conservatism has been striven for by the author and the several revisers in every part of the work that appeals particularly to dwellers in localities so removed that the doctor _cannot come at all_. Especial delicacy was also sought in the treatment of a chapter which, it is hoped, will aid parents to guide their children in sexual matters. The illustrations represent helpful, normal conditions (with the exception of some necessary representations of fracture, etc.) with instructive captions aimed to make them less a sensation than a real benefit; and no pictures appear of a sort to stimulate mere morbid curiosity. The greatest sympathy and appreciation of this work have been shown by the progressive and recognized practitioners who have seen early copies. They recognize it as a timely attempt to create and compile health literature in a form most complete within its limits of space, and in a manner most helpful and sane. The eager curiosity regarding _themselves_ that has been sweeping over the American people has been diverted into frivolous and harmful channels by much reckless talk and writing. A prominent newspaper, in its Sunday editions, recently took up the assertion, in a series of articles, that appendicitis operations resulted from a gigantic criminal conspiracy on the part of surgeons; that a sufficient cure for appendicitis, "as any honest doctor would tell you," is an injection of molasses and water! The endless harm done by such outright untruth is swelled by a joining stream of slapdash misinformation and vicious sensation, constantly running through the press.