In the preface to The Openness of God, the authors define Open Theism:
God, in grace, grants humans significant freedom to cooperate with or work against God’s will for their lives, and he enters into dynamic, give-and-take relationships with us. The Christian life involves genuine interaction between God and human beings. We respond to God’s gracious initiatives and God responds to our responses… and on it goes. God takes risks in this give-and-take relationship, yet he is endlessly resourceful and competent in working toward his ultimate goals. Sometimes God alone decides how to accomplish these goals. On other occasions, God works with human decisions, adapting his own plans to fit the changing situation. God does not control everything that happens. Rather he is open to receiving input from his creatures. In a loving dialogue, God invites us to participate with him to bring the future into being.