We shall lead your interest away from "vague mysticisms" and emphasize
such phases of scientific psychological theory as bear directly on
practical achievement.

We shall give you a practical working knowledge of concentrative mental
methods and devices. We shall clear away the mysteries and
misapprehensions that now envelop this particular field.

In the present volume we shall begin with a discussion of certain
aspects of the relation between the mind and the body.

[Sidenote: Psychology, Physiology and Relationships]

However we look at it, it is impossible to understand the mind without
some knowledge of the bodily machine through which the mind works. The
investigation of the mind and its conditions and problems is primarily
the business of psychology, which seeks to describe and explain them.
It would seem to be entirely distinct from physiology, which seeks to
classify and explain the facts of bodily structure and operation. But
all sciences overlap more or less. And this is particularly true of
psychology, which deals with the mind, and physiology, which deals with
the body.

It is the mind that we are primarily interested in. But every individual
mind resides within, or at least expresses itself through, a body. Upon
the preservation of that body and upon the orderly performance of its
functions depend our health and comfort, our very lives.

[Sidenote: Abode and instrument of Mind]