As the first full introduction written for a general audience about the life and significance of Ibn 'Arabi (1165-1240), this volume long fills an acute gap in the general literature about Sufism in English. Ibn 'Arabi can rightly be regarded as the greatest mystical thinker in the history of Islam and as might be extrapolated from this study, perhaps some future global mysticism that is inter-sectarian. In the Islamic world Ibn 'Arabi is often referred to honorifically as al-Shaykh al-Akbar (the Greatest Master). Among the literalists and reactionary legalists in Islam the profound readings of the Qur'an and hadith, that is the staple of just about everything the Shaykh al-Akbar' wrote, is regarded with shrewd suspicion, if not outright hostility and censor. Among a core of Sufis the Shaykh al-Akbar's works have been savored with a relish and delight as often his lengthy considerations show a nearly unfathomable grasp for the living presence of the divine in all aspects of life. Any mystic can find much to ponder in a studied reading of Ibn 'Arabi's texts. For the many Christians and some Jews who are still perhaps unconsciously swayed by the centuries of anti-Islamic polemic in the west, an astute reading of Shaykh al-Akbar's work should banish many of the silly sectarian ideas that cling to our ideas about Islam. Muslims themselves are still extreamly divided over the worth of Shaykh al-Akbar's views and common misattributions to him of pantheism and even incarnationism are still common slurs betraying a willful misreading of Shaykh al-Akbar's ideas. Though it is unlikely that The Unlimited Mercifier will seriously affect this perennial debate about Shaykh al-Akbar's ultimate worth as a Muslim, Hirtenstein does offer a useful introduction to ibn 'Arabi that has not existed in English before. I believe that as scholarly work proceeds on translating the profound depth of Islam as a spiritual path toward knowing self and the divine will become more widely appreciated. The perspective of Shaykh al-Akbar, acknowledged and not, definitely sets the standard of any spiritual reading of the Qur'an. Also in the emerging world spirituality ibn 'Arabi may yet play an unique role is forging a link between the monotheisms of the west to the pantheisms and non-theisms of the east and of a rationalist scientific humanisms of modernity. The Unlimited Mercifier provides not only an introduction to the life and ideas of ibn 'Arabi but without too strong a reading between the lines that the importance and perennial relevance of Shaykh al-Akbar's ideas for emerging global civilization become apparent. Given this breath I highly recommend this introduction and eventually a closer consideration of the of Shaykh al-Akbar's works as available in the works reviewed below. Special note of SUFI PATH OF KNOWLEDGE and SELF-DISCLOSURE OF GOD by William C. Chittick should be noted by sincere students.