This work is a translation of the book on Anthropology (Insan shinasi) written as part of the series of six books on the subject of Foundations of Islamic Thought (Mabani Andishe Islami). In this work, we have translated the section which describes the necessity of religion, prophethood, and Imamate for human beings to attain the real felicity and the perfection of the soul. The first chapter presents and justifies the claim that a super-rational source of knowledge is necessary for identifying the path to felicity and this source is the religion brought by the Infallible prophets. The second chapter discusses the truthfulness of Islam through examining its most important miracle, the Quran. It also elaborates the impossibility of any verbal distortions in the Quran. The third and the fourth chapter deals with the finality of Islam and what it entails; the eternality and the comprehensiveness. The last chapter discusses the concept of Imamate as a continuation of prophethood. It also delineates the Divine appointment of Twelve Imams as the successors to the last Messenger.