Publisher's Synopsis
"A collection of essays upon various subjects, its title taken from the opening one, which is also the longest and most important. The first portion of this essay, appearing in an English periodical, attracted much attention and brought to its author a stream of correspondence which he utilizes in continuing the subject and giving much good advice. His notion is that most people let their brains deteriorate as they do their bodies by not giving them stiff enough exercise, and he considers the various means by which they can put their mental organs through a course of training for the purpose of reaching a higher state of efficiency."
