Islam Reviewed by M. Ali explores the differences between the Bible and the Koran and Christianity and Islam.
http://www.beholdthebeast.com/islam_reviewed.htm
Read directly online for free:
http://www.beholdthebeast.com/islam_reviewed_contents.htm
Hard copy
http://www.ellisskolfield.net/books
Another great book by Ellis and have read it a couple of times and is a great addition to the library!