In their "Books of Birds", Ahmad Gazzali, Pour-e Sina, Shahaboddin-e Sohrevardi, and even Ibn-e Moghaffa in "Hamamatol Motavvagha" (The Riged Dove) of his Kelila va Dimna have dealt with the story of the birds. But the allegory of Attar's Manteghotteir on the one hand, and its mild alliteration to clarify the concept of pantheism on the other, have made Attar's poetry outstanding. The present essay intends to deliver some historical and literary backgrounds of Attar's Manteghotteir and its intlence upon the literature after the poet. In the eighth section of his Hasht ketab, entitleb "Ma Rich, Ma Negah" (Nothing we Are, Jast A Glance), Sohrab Sepehri, our coeval poet is a reporter of the mysterious realm of sheikh-e Eshragh which is similar" to the allegorical realm of Attar.Attar and Sepehri, although different in time and language techniques, enjoy a same chore of thought. The thought of the both is mystical: Keeping aloof from the present foreing land where man feels lonely, passing from strange and dreadful valleys, and reaching the last city of Gnostics. A quest though which man comes to revelation connects these two mystical poest together. A reveiation that comes to you after you surpassed the realm of knowledge and made a camp beyond the domain of wisdom.