Day and Night on the Sufi Path

The first textbook of Sufism is the Qur'an; there is no principle of Tasawwuf that cannot be traced back to the Holy Book. The Sufis read the Qur'an for its inner meaning, but they do not claim this is the only meaning. The clear legal rulings, the moral exhortations and warnings of the Book, are not abrogated by the batini tafsir (inner exegesis) of the Sufis, but neither can the Noble Qur'an be limited to its legal and moral dimensions. If all the seas were ink for the tafsir of the Qur'an, they would be exhausted twice over before all its meanings were unveiled. Inner and outer co-exist within the Book, depend upon each other, and inform each other; in the words of the Surah Ha Mim Sajdah, I will show them My signs on the horizons and in their own souls until they are satisfied that this is the Truth. Is it not enough for you, that I am Witness over all things? [Q. 41:53]. 
The Sufi Path, insha'Allah, has the power to place one in the near Presence of Allah--a Presence which, whether or not we are always conscious of it, alchemizes the Heart. The changes the Heart undergoes by the power of this Presence have been recorded by the Sufis over many centuries, and some of the operative laws behind these changes discerned and defined. This book contains only one small drop from that vast ocean of knowledge; it attempts to define a number of the spiritual states and transformations of the self often encountered over the course of the Path--but as the author's own shaykh reminds his followers, in reality there is only one state--Allah.