As disciples of the Lord Jesus Christ, our individual responsibility is to learn what we should learn, to live as we know we should live, and to become what the Master would have us become. Learning, doing, and becoming are central to our spiritual development and happiness in mortality and our progress in eternity. Elder Bednar's previous book, Increase in Learning, focuased on patterns related to the learning imperative. Act in Doctrine explores patterns related to our obligation to translate what we know into what we do, thereby turning from focusing on one's self to focusing on the Savior. Elder Bednar discusses the importance of Christ's character in accomplishing the Atonement, the difference between testimony and conversion, what moral agency means and why it is central to the plan of salvation, and the vital role of teachers. As with Increase in Learning, this book will have extra-wide margins for recording thoughts and questions and a DVD with additional learning resources.