Book excerpt: The Summons of the Lord of Hosts brings together in one volume several major letters written by Baha'u'llah, Prophet and Founder of the Baha'i Faith, to the monarchs and leaders of His time. In these magnificent documents He exhorts world leaders to accept the basic tenets of His Faith, sets forth the nature of His mission, and establishes the standard of justice that must govern the rule of those entrusted with civil authority. Written between 1868 and 1870, leaders of the East and West are called upon to accept His teachings on the oneness of God, the unity of all religions, and the oneness of humanity. Among the leaders specifically addressed are Napoleon III, Czar Alexander II, Queen Victoria, Nasiri'd-Din Shah, and Pope Pius IX. The Summons of the Lord of Hosts is a vitally important resource for those interested in the scripture and history of the world's great religions.