The Spheres of Islam, Iman, Ihsan & Irfan

It is a very beneficial and informative book. But I have to admit that it lost me in the final two sections where the author discussed those slaves of Allah who have attained gnosis. It all seemed way above my level of understanding. Admittedly, the author, in his conclusion, mentioned that he only included those final sections to motivate students of knowledge to strive towards such a status. He emphasised, though, that one must first work on fulfilling all the obligatory actions required by the Shariah and refrain from sins.