This book is based on three lectures delivered by Dr. Mohammad Ali Shomali on 8th to 10th July 2016 at Sophia Institute University in Loppiano, Italy in the first round of Wings of Unity project. In this book, the author discusses significance of unity of God in different aspects of islamic thought and then goes on exploring God's plan in His creation and legislation for establishing unity among mankind. The book ends with reflections about end of the time and coming of Imam Mahdi and Jesus and their collaboration in establishing universal peace and justice.