I. The second of the three books which form this work was published apart, with the title of Essay, in 1826. In 1826-27, it was reproduced together with the first, also called an Essay, in the collection of small treatises to which I gave the name of Philosophical Minor Works ("Opuscoli Filosofici"). The third is new.<br><br>All three books treat of the same subject, but under different aspects. Although each book may stand by itself, and in a certain way may be said to exhaust its own special theme, nevertheless they are mutually related in such a way that each helps to complete the others. For this reason, I have now thought it advisable to publish them together as a single work, entitled Theodicy.