I was given this book by a Turkish man who told me that Fethullah Gülen had changed his life and made him a better person and less angry at the world. There may be many others like him who were thus inspired by Gülen. To his followers, Gülen is an inspiration for peace, tolerance and interfaith dialogue.
However, I also know that Gülen is a controversial figure, who has been declared a terrorist by the Turkish President Erdoğan, has been living in exile in the United States, and at least one journalist (Ahmet Şık) sits in prison for writing a book about him and his network of schools and other organizations that are directly or indirectly connected with him and "the Gülen Movement". I read this book hoping to find out more, but his schools are discussed very briefly.
I might recommend this book to a Muslim friend, as many of the messages are positive and appeal to a Muslim audience. He extols the virtues of Islam as a religion of peace and tolerance that can improve people's lives and society on the whole. I have learned more about Islam and Sufism from this book and I became more convinced of a beneficent and cooperative interpretation of Islam that many if not most Muslims adhere to. However, it seems according to Gülen that Muslims past and present are beyond criticism or else they are not Muslims. It is one thing to argue that terrorists can never be true Muslims (and true Muslims can never be terrorists), but it is still problematic to argue that Muslims have only fought war defensively and honorably, and that the problem with the modern days is that Islamic states have not been realized and people have not returned enough to Muslim principles. His book has a strong and repeated denunciation of terrorism, with some fair insight of its causes but also with dubious proposals for solutions (the world must return to religion and Islamic principles of peace and tolerance). To be fair, I shouldn't have expected otherwise from a Muslim cleric.
The essays and lectures of Fethullah Gülen may be an inspiring call for peace and understanding from an Islamic perspective for some or a disappointing myopia of globalization and religion for others, with a very shadowy assessment of religion and politics in modern-day Turkey.