The theodicy essays of Gottfried Leibniz are considered landmark examples which treat the subject thoroughly and comprehensively with lengthy and incisive philosophical discussions.

Theodicy is defined as the study of the question: "Why does evil occur in a world with a God who is good?"

Leibniz was far from being the only scholar and philosopher troubled by evil, which he viewed as a problem that required answering from a religious and philosophical perspective. Authoring his treatises in the early 18th century, Leibniz ably details his own and past arguments on the theme of theodicy. It was arguably the issue which occupied (and preoccupied) his mind more than any other: indeed, this book represents the only book-length treatise ever written by Leibniz.

The text consists of a number of essays, in which Leibniz takes a three-pronged approach to theodicy:

Firstly he examines the essential goodness of the divine, discussing the traits and virtues of the Lord as manifest in the religious canon and in holy figures such as Jesus Christ and various Saints. Various matters, such as the notion that God may not be as all-knowing as assumed, leading to various occurrences of evil, are raised.

Secondly Leibniz turns to man, who he feels is underpinned by a range of essential freedoms and liberties that enable him to exercise his character and nature. The virtues and vices which make up the human character are discussed, with Leibniz remembering the notion that God created all men in his own image.

The third component of Leibniz' inquiries regard evil, and its origin in the religious canon. He differentiates between what he terms physical evils and moral evils, and cites a number of philosophers both ancient and contemporary in support of his statements. The concept of the 'holiness problem', which posits that complications involved in God's relationship with Earth cause evil, is also raised.

Soon after his publication of his essays, Leibniz was famously lampooned by his contemporary Voltaire, who was moved to author his mockery on the subject. However over the centuries the essays Leibniz authored on theodicy have gained praise and recognition, and are commonly supplemental texts in philosophy courses. The work is also controversial, given that Leibniz implies that God himself is the cause of evil through the complex causality of his influence.

This edition of the text includes all the original appendices, which include subsequent reflections on the original book. The translation to English from Norwegian by scholar E. M. Huggard is among the most appreciated to this day.