I am reading a really interesting book, Daughter of Fire, by Irine Tweedie.
In 1961 Ms. Tweedie traveled to India to study with a Sufi teacher. This book is her journal. I am still relatively at the beginning of the book--it's a big book--but find the developing relationship between Tweedie and her teacher fascinating. Also, it's interesting to see what it looks like when someone makes a decision for big spiritual transformation, and to witness their changes.
Eventually Ms. Tweedie became a Sufi teacher herself. I found her by reading Love is a Fire, written by one of her students, Llewellyn Vaughan-Lee.
Love is a Fire is one of the most beautiful books I have read in describing the mystical experience. Very inspirational.