Leibniz wrote two books; a considerable number of articles in learned
periodicals; and an enormous number of unpublished notes, papers and
letters, preserved in the archives of the Electors of Hanover not because
of the philosophical significance of some of them, but because of the
political importance of most of them. From among this great mass various
excerpts of philosophical interest have been made by successive editors of
Leibniz's works. It may be that the most profound understanding of his mind
is to be derived from some of these pieces, but if we wish to consider the
public history of Leibniz, we may set them aside.

Of the two books, one was published, and the other never was. The _New
Essays_ remained in Leibniz's desk, the _Theodicy_ saw the light. And so,
to his own and the succeeding generation, Leibniz was known as the author
of the _Theodicy_.

The articles in journals form the immediate background to the two books. In
1696 Leibniz heard that a French translation of Locke's _Essay concerning
Human Understanding_ was being prepared at Amsterdam. He wrote some polite
comments on Locke's great work, and published them. He also sent them to
Locke, hoping that Locke would write a reply, and that Leibniz's reflexions
and Locke's reply might be appended to the projected French translation.
But Locke set Leibniz's comments aside. Leibniz, not to be defeated, set to
work upon the _New Essays_, in which the whole substance of Locke's book is
systematically discussed in dialogue. The _New Essays_ were written in
1703. But meanwhile a painful dispute had broken out between Leibniz [34]
and the disciples of Locke and Newton, in which the English, and perhaps
Newton himself, were much to blame, and Leibniz thought it impolitic to
publish his book. It was not issued until long after his death, in the
middle of the century.