Dr. Paul quickly brushes aside the false notion that epidemiology is a statistical scoreboard of epidemics, their origin and control. He discusses epidemiology as being concerned with "the circumstances under which disease occurs, where diseases tend to flourish and where they do not." His concept of etiology of diseases is discussed in a very interesting way by utilizing agricultural similes of "seed," "soil," and "climate." The "seed" applies to the causes of the disease, whether it be a singular agent or comprised of multiple factors. The "soil" refers to the host and its condition when the seed is sown. The "climate" represents environmental factors which affect the seed and soil interaction.
Separate chapters deal with the history of epidemiology, experimental epidemiology, the statistical methods and measurements commonly used, factors in host susceptibility, geographic epidemiology, vectors, and the socioeconomic factors in disease.
The methods of study are then applied to diseases