Book form.
There have only been two Catechisms of the entire Catholic Church in its 2000 year history: The "Catechism of the Council of Trent" (1566 AD), and the "Catechism of the Catholic Church" (1997). The Holy See owns the copyright.
The Catechism of the Catholic Church, abbreviated to The Catechism or CCC, is the official and universal catechism (or catechetical text) of the Catholic Church.<ref>[ http://www.vatican.va/archive/ccc_css/archive/catechism/ccc_toc.htm ]
The Catechism of the Catholic Church, which I approved ... and the publication of which I today order by virtue of my Apostolic Authority, is a statement of the Church's faith and of catholic doctrine, attested to or illumined by Sacred Scripture, the Apostolic Tradition and the Church's Magisterium. I declare it to be a sure norm for teaching the faith and thus a valid and legitimate instrument for ecclesial communion." - Pope John Paul II (CCC pg 5)
<ref>[ http://www.vatican.va/archive/ccc_css/archive/catechism/ccc_toc.htm ]