The present book, Science of Da’wah (علم الدعوة), is a new dimension of thought process which has not been mentioned in the Islamic literature. However, the highest Allah Rabbul ‘Alamin has introduced the matter of Da’wah (Invitation) in a scientific way in verse 125 of Nahal. In this verse, the philosophical terms Wisdom (Hikmah – حكمة), Sermonizing (المواعظ) and Argument (جادل) are connected in a logical fashion. Therefore, in the present book the wisdom tringle, wisdom process tringle, Da’wah methodology, structure of a Da’wah organization, the decision-making process of a Da’wah organization, perspectives of the sermon, sermonizing technique, the science of argument, appearance and approach of arguer (Daa’ee), and few selected topics of argument that are usually Daa’ee faces during Islamic Da’wah works are explained.