In His Mushkilat al-Hadith, Yahya Muhammad denies knowledge and innocence of Shiite Imams through presenting such proofs as the way companions of later Shiite Imams dealt with the issue of imama, formation of various Shi‘a sects, perplexity and dispute of Shiites as to imama of the next Imam in every era, not presenting al-Kafi to four vicegerents of the twelfth Imam, and lack of belief in the knowledge and innocence of Imams manifested in the specific perspective of school of Qom as to exaggeration. Yahya’s claim, however, has no sense of validity; for the social-political situation of Shiites in later Imams’ time, caused by political pressure and associated with severe dissimulation, made availability of Imams limited and resulted thereby in less hadith transmission. Such factors as preparing Shiites for entering the occultation era, commitment of Shiites to correct recording of chain of transmissions, and loss of letters and writings of Imams had also reduced direct narration from their contemporary Imams. Not presenting al-Kafi to four vicegerents of the twelfth Imam is also caused by the atmosphere of insecurity and dissimulation, existence of evidence of authenticity of hadiths of al-Kafi in Kulaini’s view, and lack of direct mutual relation between kulaini and four vicegerents; it is not a sign of Kulaini’s doubt as to knowledge and innocence of Imams or his distrust of their vicegerents. On the other hand, enumeration of Imams’ virtues and divine qualities in hadiths they have collected in their books is a sign of deep belief of scholars of school of Qom in the knowledge of Unseen as well as innocence of Imams and their divine vicegerence.