ONLY a few brief lines of explanation and editorial
acknowledgment are necessary in launching this
second English collection of Dr Jung's essays. The first paper
in the book, "On Psychical Energy," was framed soon after
the author had finished the Psychology of the Unconscious.
It was, however, pressed aside by the greater importance
of the type-problem. The author's brilliant study on
psychological types intervened, and this paper, originally
entitled "The Theory of the Libido", was taken up again only
last summer. It is a work of the first importance, and readers
who have suffered fatigue in the restricted purlieus of psycho-
analytical literature will feel again in this paper the exhilaration
of a wide scientific horizon.

The papers immediately following this essay, namely
"Spirit and Life, Mind and the Earth", "Analytical
Psychology and 'Weltanschauung'", and "Woman in
Europe", represent Jung's latest work, and they all reveal
how far his psychological outlook has extended beyond the
characteristic confines of psycho-analytic theory. Besides
these latest contributions, there are included several other
papers delivered by Jung to various bodies both in this country
and on the Continent, dealing with a variety of problems and
aspects of modern life. Since many of these papers were in
the nature of an explanatory outline of his ideas to a lay
audience, a certain amount of overlapping and repetition was
unavoidable. However, what repetition there is will prove
to be an asset to all those students who wish to get a thorough
grasp of Jung's psychological conceptions.

With regard to the "Love Problem of the Student", it
should be borne in mind that this paper was written and

-ix-