- Islamic Studies (Christian influences in Muslim tradition,[47] the concept of time and calendar in Islam,[48] Quranic demonology,[49] the concept of al-ʿArāf (‘Muslim purgatory’),[50] the Qur'an hermeneutic in the world of Islam,[51] Islamic jurisprudence and the rules of Sunni Muslim theology[52] aspects of divinization according to Farīd-al-dīn ʿAṭṭār Nīšāpūrī (died ca. 1221),[53] the concept of the universality of Islam,[54] the Muslim eschatology,[55] the slavery[56] and the status of women in Islam,[57] the concept of Jihad in Sunni sources (Qur'an, Sunnah) and the modern modifications and perceptions of Jihad in the Islamic world.[58] Jihad in various aspects contexts (historical, theological and dialogue of life).[59] Author of the first Polish Concordance of the Qurʾān.[60] He has translated and commented on several Hadiths.)[61]