Attar is creator of the 'Flying Logic' (Mantegh ol teir) dealing with the mystery of the mythical Phoenix (In Persian called 'Simorgh'). The birds of the world set forth in search of their king, 'Simorgh'.  They are led by the hope; their quest takes them through seven valleys where many obstacles are presented. They undergo many trials as they try to free themselves of what is precious to them and change their state. In first valley they ask for wine to dull the effects of dogma, belief, and disbelief in their own lives. In the second valley, the birds give up reason for love. In the third valley the birds discover that their worldly knowledge has become completely useless and their understanding has become ambivalent. The fourth valley is introduced as the valley of detachment, i.e., detachment from desire to possess and the wish to discover.

The birds begin to feel that they have become part of a universe that is detached from their physical recognizable reality. Next, they enter the fifth valley, where they realize that unity and multiplicity are the same, and they have become entities in a vacuum with no sense of eternity. More importantly, they realize that God is beyond unity, multiplicity, and eternity. In the sixth valley, the birds become astonished at the beauty of the Beloved. Experiencing extreme sadness and dejection, they feel that they know nothing and they understand nothing. They are not even aware of themselves. Only thirty birds reach the abode of the Simorgh. But there is no Simorgh to be found at the final stage. The Simorgh's chamberlain keeps them waiting long enough for the birds to figure out that they themselves are the si (thirty) morgh (bird). The seventh valley is the valley of depravation, forgetfulness, dumbness, deafness, and death. The present and future lives of the thirty successful birds become shadows chased by the celestial Sun, and in this state of loss in the Sea of existence, they are the Simorgh.

Attar is one of the most famous mystic poets of Iran. His works were the inspiration of Rumi and many other mystic poets. Attar and Sanaie were two of the greatest influences on Rumi in his views. Rumi has mentioned both of them with the highest esteem several times in his poetry. Elahi Nameh, Asrar Nameh, Mokhtar Nameh, Mosibat Nameh and Sharh Al-Qalb are some of his well-known works.

He was the son of a prosperous chemist, receiving an excellent education in Arabic, theosophy and medicine. He helped his father in the store and, on his father's death, owned his own store. The people he helped in the pharmacy used to confide their troubles in Attar and this affected him deeply. Eventually, he abandoned his pharmacy store and traveled widely to Kufa, Mecca, Damascus, Turkistan, and India, meeting with Sufi sheikhs. He returned promoting people to dull the effects of dogma, belief, and disbelief on their lives and to free themselves of what is precious to them and change their state of mind.

Some scholars say he was killed during the raid and destruction of his city by the Mongol invaders. His tomb is in Neishapour.

References:

Http://en.wikipedia.org