Please see below link to a book titled ‘The Defense of the Sunnah: An Analysis of the Theory and Practices Of Tasawwuf (Sufism)’ by Ibrahim Muhammad Hakim ash-Shaghouri. The title speaks for itself, however, below is an excerpt from the introduction stating the aims of the book:
The purpose of this book is to educate the reader about some of the beliefs of Sufis and their practices, and to demonstrate how they are in full accordance with the Shari’a Tasawwuf from the very beginning has always been integral to the Din, functioning as the realization and implementation of the pillar of Ihsan in the being of the Muslim. Tasawwuf is not a madhhab, nor a sect, nor an ideology, nor a cult, nor a foreign import, nor an heretical invention. It is nothing other than a science concerning the reality of Allah, His Messenger, and the self, transmitted faithfully and without interruption from the Prophet (asws) himself.
It is the belief of the writer that the current corruption of the Ummah and its egradation is a direct result of – among other things – the crumbling away of the pivotal pillar of Ihsan as realized through the practice of Tasawwuf and its principles.
More details on the book and how to purchase can be found at the following link insha Allah: