A couple of years ago I was reading up on "Judaism for Dummies" and I found it to be a nice way learn a bit more about the religion. Online reviews of the book ran from serious to quirky and every flavor in between - some liked it, while others could do without.
After 9-11 I felt that it might be helpful to employ the same series "Islam for Dummies" to prime myself on the religion of peace.
Surprisingly, it was a 5 star read for anyone and everyone that so much as touched the book. I figured I really didn't need to bother with the book.
Get a copy of the real deal, preferably for free from your neighborhood mosque during Ramadan (haha).
People need to read the Koran for themselves, no cliff notes, etc. Excerpted passages just don't do it justice to get a real understanding.
It will probably take you weeks to read it, since you will lose your lunch/dinner often and have to put it down for a day or two.