I have done a lot of my own research on Islam, and so there is much in Robert Spencer's "Politically Incorrect Guide To Islam" that I already knew.
However, the majority of people out there DON'T know this stuff, and that is why I think everyone, Muslim and non-Muslim, should read it. It might well save their lives.
Of course, many will simply dismiss the contents of this book as the work of a "racist" who is trying to incite hatred against Muslims. Many reviewers here have already stated that Spencer quotes the Qur'an and hadiths "out of context" and misrepresents the religion and its teachings. Of course, they have never challenged any of the assertions Spencer makes intellectually, nor have they ever explained what it is that he has taken out of context. For these defensive soldiers of political correctness, NOTHING will ever cause them to take note of the truth about Islam.
And of course, Spencer's aim ISN'T to incite hatred against Muslims, the majority of whom, he acknowledges, are peaceful and civilised. His aim is to draw attention to the aspects of Islam that jihadists are using to justify their actions, so that we may better understand our enemy and thus take necessary and appropriate steps towards defeating him. This book is a call for non-Muslims to pull the wool from their eyes and recognise that the problem we face today isn't "terrorism" or "religious fundamentalism"; it is Islamic jihad. And it is a call to peaceful, moderate Muslims to examine the contents of their Holy Writ, and the teachings of their Prophet, and work towards a reform that will allow Muslims and non-Muslims to live in harmony without persecution and the threat of war. This is not too much to ask, but the veil of political correctness has made it increasingly difficult to conduct any kind of serious analysis of these issues, instead labeling anyone who criticises Islam as "hate-mongers". This puts us all in danger.
Overall, an excellent book. It is elegantly worded and clearly set out in bite-size sections. Anyone with an interest in preserving the freedom of Western civilisation (which, as Spencer explains in the book, has done much for which we should be proud and thankful) should read it. I intend to buy his other works.