Best book for Mormon's

I’ve been chatting with a couple of Mormon’s online and we came to a deal that once they are done with their missions (they are not aloud to read ‘unapproved’ books while missionaries) they will read a book of my choosing if I read the Book of Mormon. The first one is done in about 6 months so I’ve got some time.

So, which book would be best to give to a Mormon?

Michael Coren, why Catholics are right

What about the Catechism of the Catholic Church? That would answer a lot of questions and also explain many of the Church teachings.

The Continuity of the Catholic Church by Bishop Duane G. Hunt D.D. (Bishop of the Salt Lake diocese, 1937-1960)