Sufism and Islamic spirituality by professor Sayyed Hosain Nasr, a link

A link to a talk on Islamic spirituality and Sufism by professor Sayyed Hosain Nasr of George Washington University. He is regarded as an authority on Islam and Sufism. His under graduate degree is in physics and mathematics from MIT. Masters from Harvard in earth sciences and  a PhD in history of science and philosophy also from Harvard in 1958. He has published about 50 books and several hundred articles.