As I have discussed in other posts, there are a few good extensive catechisms, the best being The Catechism of the Council of Trent. Easter is the time of year we try to bring people into the catholic church, and a good handle on the faith is required. To start young children up to the age of about 10 a book that is a good start is “I Believe in God: The Apostles’ Creed” by father Lawrence G. Lovasic, S.V.D.
For more mature children, and pre-teens up through college, who are unable to find time to read the more extensive catechisms, as well as for non-Catholics interested in the faith “What Catholics Believe: Sketch-Talks” by the same author above father Lawrence G. Lovasic, S.V.D. is excellent, in my opinion. It covers all the bases and is 102 pages long, and measures 4.2” X 7”. It can fit in one’s pocket and can be read in about 3 days if you are a slow reader and want to take a little time to “chew on” the concepts laid out there.
Now if you are a very busy adult who is considering the faith but want something short and sweet or an adult who wants a review of his faith “The Catholic Layman’s Guide: A Brief outline of what we should know and do,” by Father R. G. Bandas is a good choice. It is a normal book sized pamphlet about 47 pages long.
All 3 carry an Imprimatur.