This is a great, great book. It is a philosophical journey through the Islamic landscape in the modern world. The author attempts to step back and is not afraid to critique much of Islam's approach to modernity: denial, covert acceptance and militant attacks against.
He believes in Islam as a viable solution to the modern world's ailments but realizes also that isolationism is not the solution; in fact, it's hypocrisy as many in the Islamic world embrace various aspects of modernity.
Using Christianity's history with modernity as a model, he challenges Muslims that Islam is not free from the secularism that has resulted. It's only a matter of time until it comes pounding on the door. In fact, it's already begun to chisel at the foundations. The West is not completely to blame. Muslims must own up to the challenge and deal with it. This is his rallying cry.
He takes Christianity to task for some of the results of this struggle with modernity and dissects some of its approaches to and interactions with Islam but the bulk of the book is directed toward Muslims dealing with, if you will, the 'real world'.
Perhaps the fundamental flaw in the book is that it is quite apparent that his view of the West is European, i.e. England. His perception of the Christian (or that of a religious worldview in general) malaise in the light of modernity and its seeming irrelevance does not seem to fit so much in America. Because of this, Christianity has manifest in a unique way in America and it is quite apparent he has missed out on this. While it is obvious secularism is on the rise in the U.S., atheism is not so pronounced here. However, considering the trend of much of the Church, perhaps his book is prophetic.
And in discussing the Christian tradition and its seeming vacuity, he is underestimates the rise in evangelical Christianity (e.g. Pentecostalism, the whole charismatic movement) taking place on many levels in the U.S. (and worldwide, actually). Though he makes a few mentions of it in the endnotes it would be interesting to hear his views on this as the book is from 1990.
Be forewarned: this book is steeped heavily in the western philosophical tradition and gets quite dense in places. It is not a light read. This isn't a bad thing but it must be digested slowly in order to follow him. Though you may not agree with all his conclusions, it is a well-reasoned challenge.