Chapter I is given over to showing that God is substance which is eternal; that God is the first cause and is the cause of himself. He makes himself known through himself and that. outside God there is nothing at all,
What is surprising is there is no mention of God being identical with Nature.
Chapter II is concerned with the nature of God and Spinoza ends it with a converation between characters called The Understanding, Love, Reason, and Desire.
Immediately after the first is a second dialogue between charaters called Erasmus and Theophilus which contains nothing new. Perhaps Spinoza was persuaded to use this form by the fact that Galileo used it in Dialogue Concerning the Two Chief World Systems. There the idea that the Earth moves around the Sun is presented in a series of discussions, over a span of four days, among two philosophers and a layman.