Based on the Baltimore Catechism, but simplified for younger children, this catechism provides the first (formal, printed) step in a spiraling study of the faith. Written for children who have been baptized (it asks "What sacrament have you received? ...Baptism."), it is intended to teach on the next sacraments, reverence and understanding of the Mass, and on sin and salvation. Given the intended age range, of course it does not cover everything; many descriptions (e.g. venial sin) are unnuanced, in anticipation of further instruction. That said, it provides catechism that even some adults may need: the difference between original and actual sin, the Immaculate Conception, the two greatest annual Feasts (Christmas is not one of them), etc.
This is a great gift for a child preparing for their first confession, especially. It should be read and studied slowly together, and it can brought to Mass as a very simple missal and prayerbook.