OK it's a really interesting book. I bought it because Mufti Kamaluddin mentioned it in one of his talks. It's around 300 pages I couldn't put it down finished it in 2 days. He speaks a lot about the Mujaddid Alf Thani (RA)'s view on ecstasy and utterances in the state of ecstasy. Really interesting. If you read the whole book with all his notes at the back you will learn a lot about early Sufis too. He discusses the difference between Ibn al-Arabi (RA)'s wahdatul wujood and Mujaddid (RA)'s wahdatu-shuhood. Shah Waliyullah (RA) comes about 100 years after Mujaddid Alf Thani (RA) and he speaks briefly about how he attempts to reconcile between wujoodi and shuhoodi understandings. He disagrees quite bluntly with Shah Waliyullah (RA) and ibn al-Arabi (RA) in favour of Mujaddid Alf Thaani. He also speaks about how one of Mawlana Jani Jaanaan's Khalifah refutes Shah Waliyullah (RA)'s attempt to reconcile between the two. In the end of the first part he finishes with ibn Taymiyyah (RA)'s view on tasawwuf and says it is very similar to the Naqshbandi-Mujaddidi practices. He shows that ibn Taymiyyah (RA) praises sufis who would not entertain ecstatic states like Abdul Qadir al Jilani, Junayd al-Baghdadi (RA) etc. The second part of the book is all translations of parts of the Maktoobaat. Anyway I wouldn't say it's a book of the Naqshbandi-Mujaddidi's, its more an academic work but not overly academic in that you can actually read it and understand it. The author studied in Indian universities and also did an MA in Harvard. If I remember correctly he was born in the 1930s so if he's still alive he'll be pretty old.