"The science of public health administration has had no abler or more attractive exponent than Dr. Mackenzie. He adds to a thorough grasp of the problems an illuminating style, and an arresting manner of treating a subject often dull and sometimes unsavoury." - Economist With a near-literary style, William L. Mackenzie (1862-1935) guides the reader through an examination of common diseases, their sources and their prevention. Defining "health" as "a mere working concept, an ideal", he offers a view on the changing health awareness of early 20th century society.