Ok this is what I finally wrote back with. Hopefully it will help someone else searching for stuff:
Sorry for the delay. I contacted the Islamic school here and they actually use this series of books for their classes. I checked them out and they are not written just for school kids, but for anyone who wants to learn -- like new Muslims. The language is adult like and the topics are on basic theology. It seems like a very good series:
The series is called Islamic Studies by Bilal Philips:
Islamic Studies Book 1 http://islamicbookstore.com/b9699.html
Islamic Studies Book 2 http://islamicbookstore.com/b9700.html
Islamic Studies Book 3 http://islamicbookstore.com/b9701.html
Islamic Studies Book 4 http://islamicbookstore.com/b8813.html
Islamic Studies Book 5 couldn't find the link but u could contact them
You could maybe purchase one set and try it out and see how it goes.
If you're looking for only one book then Islam: Beliefs and Teachings by Ghulam Sarwar is a very good basic book that covers everything: http://islamicbookstore.com/b2730.html
It is more geared to youngsters but has all the information.
Something like what you were looking for might be this one:http://www.dar-us-salam.com/store/main.mvc?Screen=PROD%20&Product_Code=109&Category_Code=Eng_Pkgs
It seems to be small booklets with the basics. I haven't read them or know anything about it but it could be good for your use.
All the above books are in paperback though so hopefully that helps.
Take care & Happy new year!