Shaykh Baha' ad-Din al-`Amili, or Sheykh Bahaee (February 1547 - 30 August 1621) was a great Shii scholar in the field of Quran, hadith, fiqh (jurisprudence), mysticism, mathematics, architecture, literature, and poetry. He wrote over 88 books in different topics mostly in Persian but also in Arabic. The present paper is concerned with one of the scientific characteristics of this great scholar that is hadith sciences: rijal, diraya, hadith terminology, hadith scholarship. To the author of the present paper Shaykh Bahaee's scholarly approach and wonderful innovations are all marvelous and praiseworthy.