Certain important points had to be passed over.

In the present volume the substance of the original lectures has been entirely rearranged and rewritten, and more than half the matter is new.
Even in the present volume, however, it has been impossible to treat the subject otherwise than in a general way.

At almost every point a really complete discussion would necessitate a much fuller analysis of facts than it has been practicable to give here.

Arguments here necessarily confined to a few pages or to a chapter, would each, for their complete elucidation, require a separate monograph.

Most readers, however, will be able to supply much of what is missing, by the light of their own common sense; and general arguments, in which, as in block plans of buildings, many details are suppressed, have for practical purposes the great advantage of being generally and easily intelligible, whereas, if stated in fuller and more complex form, they might confuse rather than enlighten a large number of readers.
The fact that the fundamental arguments of this volume were disseminated throughout the United States, not only at the meetings addressed, but also in all the leading newspapers, has had the valuable result, by means of the mass of criticisms which they elicited, of illustrating the manner in which socialists attempt to meet them; and has enabled me to revise, with a view to farther clearness, certain passages which were intentionally or unintentionally misunderstood, and also to emphasise the curious confusions of thought into which various critics have been driven in their efforts to controvert or get round them.