Basic topic of this book is to advocate the establishment of World Federation and World Government and to consider the philosophy on how we can be happy. As for the establishment of World Federation and World Government, benefits of World Federation and World Government are introduced. As for the philosophy on how we can be happy, some religious thoughts are introduced. For example, an idea which improves Einstein's theory of relativity is introduced. Basic philosophy is that we must do good if we want to be happy. Mission from God is to make a world where all people can live happily. These thoughts lead to the establishment of World Federation and World Government.