I highly recommend the book "Fundamentals of Catholicism" by Kenneth Baker, S.J., especially for Catholics who haven't been taught fundamental teachings while growing up (about God, His qualities, how they correspond with reality, etc.). Below is a link for the book with several pages of the book displayed/a preview. Enjoy

http://books.google.com/books?id=yBW8l1opH-oC&printsec=frontcover&dq=fundamentals+of+Catholicism+kenneth+baker&hl=en&ei=NDdDTbGzD8GRgQfZtPSNAg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CDAQ6AEwAA#v=onepage&q&f=false