This book was originally called De Libero Arbitrio Diatribe Sive Collatio which means "On the Free Will, Discourses and Comparison," and it contained the core argument of Erasmus's philosophical-religious belief that human beings were autonomous by God's soverign design.
He responds to Luther's theories first, isolating their disagreement on the issues of divine justice, which is kind of like the Hindu conception of Karma, except where Jesus Christ is the judge of human fates. Luther was of the opinion that God's sovereignty was observable in the unique synchronicities that fill a human life, pointing to God's divine orchestration. (It must be noted that The Freedom of the Will is partially a response to Luther's writings, and Luther responds to this publication as well, et cetera).
He rejects Luther's argument and says that although God has sovereign knowledge of the future, because God is technically able (hypothetically) to impose his will specifically—but Erasmus says God is more like an astronomer who knows the order of heavenly events. He says that God has technical knowledge about all the machinery of existence, but in an open way.
He says this is helpful in the question of the problem of evil. He says that the God of the Bible simply could not have ordained that humans sin, or that malice should exist, or that violence and tragedy should occur. Human evil is a human invention, says Erasmus. He says when one properly understands the nature of grace, this answer becomes less emotionally disturbing.
